Stellar Biotechnologies Announces Pricing of $5.5 Million Public Offering

Stellar Biotechnologies Announces Pricing

of $5.5 Million Public Offering

LOS ANGELES, May 11, 2018 /PRNewswire/ - Stellar Biotechnologies,

Inc. (Nasdaq: SBOT), a leading manufacturer of a key protein utilized in multiple immunotherapy development pipelines targeting

Alzheimer's, lupus and cancers, among other diseases, today announced the pricing of a public offering of an aggregate of 2,075,472

units (the "Units"), with each Unit consisting of (i) one common share, no par value per share (the "Common Shares")

or Common Share equivalent, and (ii) one warrant to purchase one Common Share (the "Warrants"). Stellar is offering

the Units at a price of $2.65 per Unit.

H.C. Wainwright & Co. is acting as the exclusive placement agent

The warrants will be exercisable immediately at an exercise price

of $2.65 per share and will expire five years from the date of issuance. The Common Shares or Common Share equivalents and the

accompanying Warrants can only be purchased together in this offering but will be issued separately. This offering is expected

to close on or about May 15, 2018, subject to customary closing conditions.

The gross proceeds of the offering are expected to be approximately

$5.5 million, prior to deducting placement agent discounts and commissions and estimated offering expenses. Stellar intends to

use the net proceeds from the offering for general corporate purposes, which may include research and development activities, capital

expenditures and working capital.

A registration statement on Form S-1, as amended (File No. 333-224314)

relating to these securities was declared effective by the Securities and Exchange Commission (SEC) on May 10, 2018. This offering

is being made only by means of a prospectus forming part of the effective registration statement. A preliminary prospectus relating

to and describing the terms of the offering has been filed with the SEC. Copies of the preliminary prospectus, and when available,

copies of the final prospectus relating to the offering may be obtained for free by visiting the SEC's website at www.sec.gov or

from H.C. Wainwright & Co., LLC, 430 Park Avenue, 3rd Floor, New York, New York 10022, by phone at 646-975-6996

or e-mail at placements@hcwco.com.

This press release does not constitute an offer to sell, or the

solicitation of an offer to buy, nor shall there be any sale of these securities in any state or jurisdiction in which such an

offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such state

About Stellar Biotechnologies

Based north of Los Angeles at the Port of Hueneme, Stellar Biotechnologies,

Inc. is the leader in sustainable manufacture of Keyhole Limpet Hemocyanin (KLH), an immune-stimulating protein utilized

as a carrier molecule in therapeutic vaccine pipelines (targeting cancers, immune disorders, Alzheimer's and inflammatory diseases)

and for assessing immune system function. KLH can also be used in immunotoxicology studies for monitoring the immunomodulatory

effects of drug candidates. Stellar is committed to meeting the growing demand for commercial-scale supplies of GMP grade KLH,

ensuring environmentally sound KLH production, and supporting the development of KLH-based active immunotherapies. Stellar KLH

is a trademark of Stellar Biotechnologies.

Stellar Forward-Looking Statements

This press release may contain forward-looking statements within

the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as

amended. Forward-looking statements may be identified by the use of words such as "anticipate," "believe,"

"plan," "estimate," "expect," "intend," "may," "will," "would,"

"could," "should," "might," "potential," or "continue" and variations or similar

expressions. Readers should not unduly rely on these forward-looking statements, which are not a guarantee of future performance.

There can be no assurance that forward-looking statements will prove to be accurate, as all such forward-looking statements involve

known and unknown risks, uncertainties and other factors which may cause actual results or future events to differ materially from

the forward-looking statements. Such risks include, but may not be limited to: market conditions; the satisfaction of customary

closing conditions related to the offering; the expected closing date of the offering; the expected use of the net proceeds from

the offering; changes in strategy or development plans; availability of funds and resources; anticipated requirements for operating

capital; governmental regulations and the ability or failure to comply with governmental regulations; changes in trade policy and

international law; the timing of Stellar's or its partners' anticipated results, including in connection with clinical trials;

the ability to meet the goals of Stellar's joint ventures and strategic partnerships; and other factors referenced in Stellar's

filings with securities regulators. For a discussion of further risks and uncertainties related to the Stellar's business,

please refer to Stellar's public company reports filed with the U.S. Securities and Exchange Commission and the British Columbia

Securities Commission. All forward-looking statements are made as of the date hereof and are subject to change. Except as required

by law, Stellar assumes no obligation to update such statements. This press release does not constitute an offer or solicitation

of an offer for sale of any securities in any jurisdiction, including the United States.