Notice of Interim Results

PRESS RELEASE

1 September 2015

Horizon Discovery Group plc

("Horizon" or "the Company")

Notice of Interim Results

Cambridge, UK, 1st September 2015: Horizon Discovery Group plc (LSE: HZD) (Horizon) announces today that its interim results for the six months ended 30 June 2015 will be announced on Tuesday 22 September 2015.

Dr. Darrin M. Disley, Chief Executive Officer, and Richard Vellacott, Chief Financial Officer, will host a presentation and live conference call for analysts at 9:30am on the morning of the results in the Dome Room at 1 Cornhill, London, EC3V 3ND.

ENDS

Notes to Editors

For further information from Horizon Discovery Group plc, please contact:

Consilium Strategic Communications (Financial Media and Investor Relations)

Amber Fennell / Jessica Hodgson / Matthew Neal / Laura Thornton

Tel: +44 (0) 20 3709 5701

Email: [email protected]

Panmure Gordon (UK) Limited (NOMAD)

Corporate Finance: Freddy Crossley / Duncan Monteith / Fred Walsh

Broking: Tom Salvesen

Tel: +44 20 7886 2500

Zyme Communications (Trade and Regional Media)

Katie Odgaard

Tel: +44 (0)7787 502 947

Email: [email protected]

About Horizon Discovery Group plc www.horizondiscovery.com/

Horizon is a revenue-generating life science company supplying research tools to organizations engaged in genomics research and the development of personalized medicines. Horizon has a diverse and international customer base of over 1,000 organizations across nearly 50 countries, including major pharmaceutical, biotechnology and diagnostic companies as well as leading academic research centers. The Company supplies its products and services into multiple markets, estimated to total in excess of £29 billion by 2015.

Horizon's core capabilities are built around its proprietary translational genomics platform, a high-precision and flexible suite of gene editing tools able to alter almost any endogenous gene sequence of human or mammalian cell-lines. Horizon offers almost 14,000 products, almost all of which are based on the application of gene editing to generate cell lines that accurately model the disease-causing mutations found in genetically based diseases. These 'patients-in-a-test-tube' are being used by customers to identify the effect of individual or compound genetic mutations on drug activity, patient responsiveness, and resistance, which may lead to the successful prediction of which patient sub-groups will respond to currently available and future drug treatments.

In addition, Horizon provides gene editing tools, custom cell line generation services for research and bioproduction applications, quantitative molecular reference standards, in vivo disease models, contract research and custom screening services and custom shRNA development services and off-the-shelf validated shRNA (through Horizon's partner Sirion).

Horizon is headquartered in Cambridge, UK, and is listed on the London Stock Exchange's AIM market under the ticker "HZD", for further information please visit: www.horizondiscovery.com.