Director/PDMR Shareholding

Costain Group PLC("Costain" or the "Company")

Transaction in shares by Persons Discharging Managerial Responsibility ("PDMR") and their connected persons

 Ordinary Shares of 50p each

The Company received notification on 19 December 2011 of the following transactions in its ordinary shares of 50p each ("Ordinary Shares"):

·; On 16 December 2011, Mrs Andrea Bryant, a connected person to Mr John Bryant, Senior Independent Director, purchased 5,000 Ordinary Shares at a price of £1.99 per share.

·; On 19 December 2011, Mr James Morley, a Non-executive Director, purchased (through Barclays Shares Nominees and Pershing Shares Nominees) 18,000 Ordinary Shares. The price paid for the Ordinary Shares was £1.9016 per share (2,871 Ordinary Shares), £1.9055 per share (8,086 Ordinary Shares) and £1.918999 per share (7,043 Ordinary Shares).

The Company received notification on 20 December 2011 of the following transaction in its ordinary shares of 50p each ("Ordinary Shares"):

·; On 20 December 2011, Mr Mike Alexander, a Non-executive Director purchased (through Hargreaves Lansdown Nominees) 5,313 Ordinary Shares at a price of £1.8255 per share

All the above transactions were carried out in London.

This announcement is made following notifications made in accordance with Disclosure and Transparency Rule 3.1.2R.

20 December 2011

Enquiries:

Costain Group PLC Tel: 01628 842444Tracey Wood