As filed with the Securities and Exchange Commission on February 28, 2014

Registration No. 333-             

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM S-8

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

ONCONOVA THERAPEUTICS, INC.

(Exact name of registrant as specified in its charter)

375 Pheasant Run
Newtown, PA 18940

(Address, including zip code, of registrant’s principal executive offices)

ONCONOVA THERAPEUTICS, INC. 2013 EQUITY COMPENSATION PLAN

(Full title of the plan)

With copies to:

Indicate by check mark whether the Registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act.

CALCULATION OF REGISTRATION FEE

(1)         Represents shares of Common Stock, $0.01 par value per share, of the Registrant (the “Common Stock”) that were automatically added to the shares authorized for issuance under the Onconova Therapeutics, Inc. 2013 Equity Compensation Plan (the “Plan”), on January 1, 2014 pursuant to an “evergreen” provision contained in the Plan.  Pursuant to such provision, on January 1 of each year until 2023, the number of shares authorized for issuance under the Plan is automatically increased by a number equal to the lesser of (a) a number of shares of Common Stock equal to four percent (4%) of the issued and outstanding Common Stock, without duplication, (b) 2,000,000 shares of Common Stock and (c) such lesser number as determined by the board of directors of the Registrant.  Pursuant to Rule 416 of the Securities Act of 1933, as amended (the “Securities Act”), this registration statement shall also cover any additional shares of Common Stock which become issuable under the Plan by reason of any stock dividend, stock split, recapitalization or other similar transaction effected without the receipt of consideration which results in an increase in the number of the outstanding shares of the Registrant.

(2)         Estimated solely for the purpose of calculating the registration fee pursuant to Rules 457(c) and 457(h) of the Securities Act. The price per share and aggregate offering price are calculated on the basis of $9.08, the average of the high and low price of the Common Stock as reported on the NASDAQ Global Market on February 25, 2014.

INCORPORATION BY REFERENCE OF CONTENTS OF REGISTRATION

STATEMENT ON FORM S-8

This Registration Statement is being filed for the purpose of increasing the number of securities of the same class as other securities for which a Registration Statement of the Registrant on Form S-8 relating to the same employee benefit plan is effective.

The Registrant’s Registration Statement on Form S-8 previously filed with the Securities and Exchange Commission, or SEC, on September 13, 2013 (File No. 333-191161) is incorporated by reference in this Registration Statement, pursuant to General Instruction E to Form S-8.

ITEM 8. EXHIBITS.

The Exhibit Index immediately preceding the signature page is incorporated herein by reference.

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SIGNATURES

Pursuant to the requirements of the Securities Act, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-8 and has duly caused this registration statement to be signed on its behalf by the undersigned, thereunto duly authorized in the City of Newtown, Commonwealth of Pennsylvania, on the 28th day of February, 2014.

POWER OF ATTORNEY

We, the undersigned officers and directors of Onconova Therapeutics, Inc., hereby severally constitute and appoint Ramesh Kumar, Ph.D. and Ajay Bansal, and each of them singly, our true and lawful attorneys with full power to them, and each of them singly, to sign for us and in our names in the capacities indicated below, the registration statement on Form S-8 filed herewith and any and all subsequent amendments to said registration statement, and generally to do all such things in our names and on our behalf in our capacities as officers and directors to enable Onconova Therapeutics, Inc. to comply with the provisions of the Securities Act of 1933, as amended, and all requirements of the Securities and Exchange Commission, hereby ratifying and confirming our signatures as they may be signed by our said attorneys, or any of them, to said registration statement and any and all amendments thereto.

Pursuant to the requirements of the Securities Act of 1933, this registration statement has been signed by the following persons in the capacities and on the dates indicated.

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EXHIBITS INDEX

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Exhibit 5.1

February 28, 2014

Onconova Therapeutics, Inc.

375 Pheasant Run

Newtown, PA 18940

Re:          REGISTRATION STATEMENT ON FORM S-8

Ladies and Gentlemen:

We have acted as counsel to Onconova Therapeutics, Inc., a Delaware corporation (the “Company”), in connection with the filing with the Securities and Exchange Commission (the “Commission”) of a Registration Statement on Form S-8 (the “Registration Statement”) for the purpose of registering under the Securities Act of 1933, as amended (the “Securities Act”), 858,699 shares of its common stock, par value $0.01 per share (the “Shares”), issuable under the Onconova Therapeutics, Inc. 2013 Equity Compensation Plan (the “Plan”). This opinion is being furnished to the Company in connection with the requirements of Item 601(b)(5) of Regulation S-K under the Securities Act, and no opinion is expressed herein as to any matter pertaining to the contents of the Registration Statement other than as expressly stated herein with respect to the Shares.

As your counsel, we have examined such documents and such matters of fact and law that we have deemed necessary for the purpose of rendering the opinion expressed herein.

In our examination, we have assumed the genuineness of all signatures, the authenticity of all documents submitted to us as original documents, and the conformity to original documents of all documents submitted to us as copies, the legal capacity of natural persons who are signatories to the documents examined by us and the legal power and authority of all persons signing on behalf of parties (other than the Company) to all documents.

Subject to the foregoing and the other matters set forth herein, it is our opinion that, as of the date hereof, when the Shares shall have been duly registered on the books of the transfer agent and registrar therefor in the name or on behalf of the holders and have been issued by the Company against payment therefor (not less than par value) in the circumstances contemplated by the Plan, assuming in each case that the individual issuances, grants or awards under the Plan are duly authorized by all necessary corporate action and duly issued, granted or awarded and exercised in accordance with the requirements of law and the Plan (and the agreements and awards duly adopted thereunder and in accordance therewith), the issue and sale of the Shares will have been

duly authorized by all necessary corporate action of the Company, and the Shares will be validly issued, fully paid and non-assessable.

We are opining herein only as to the General Corporation Law of the State of Delaware, and we express no opinion with respect to the applicability thereto, or the effect thereon, of any other laws.

We hereby consent to the filing of this opinion as an exhibit to the Registration Statement. In giving this consent, we do not admit that we are in the category of persons whose consent is required under Section 7 of the Securities Act or the rules and regulations of the Commission thereunder

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Exhibit 23.2

Consent of Independent Registered Public Accounting Firm

We consent to the incorporation by reference in the Registration Statement (Form S-8) filed on February 28, 2014 pertaining to the Onconova Therapeutics, Inc. 2013 Equity Compensation Plan of our report dated May 3, 2013 (except for the third paragraph of Note 18, as to which the date is July 17, 2013), with respect to the consolidated financial statements of Onconova Therapeutics, Inc., included in the Registration Statement (No. 333-189358) and related Prospectus, filed with the Securities and Exchange Commission.

Philadelphia, Pennsylvania

February 28, 2014

Exhibit 23.3

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We consent to the incorporation by reference in the Registration Statement of Onconova Therapeutics, Inc. on Form S-8 to be filed on or about February 28, 2014 of our report dated May 2, 2013, except for the third paragraph of Note 18, for which the date is July 17, 2013, on our audit of the financial statements as of December 31, 2011 and for the year ended December 31, 2011. We also consent to the reference to our firm under the caption “Experts” in the Registration Statement on Form S-8.

Iselin, New Jersey
February 28, 2014