Revenue at Canadian outsourcer CGI Group dipped by four per cent in the first quarter of 2015 to $2.5bn (£1.7bn), compared with the same period in 2014.
Meanwhile earnings rose by 24 per cent to $236m (£156m).
CGI attributed its first-quarter revenue drop to a one-off spike from its Obamacare IT contract last year. The contract was taken away from group subsidiary CGI Federal in February 2014 following a botched rollout of the HealthCare.gov portal.
The US is the firm's biggest market, where it does 27 per cent of its business, followed by Canada at 15 per cent and the UK at 13 per cent.
In 2012 CGI made significant moves into the UK market when it snapped up Anglo-Dutch outsourcer Logica for £1.7bn.
The company singled out health, justice and utilities as strong markets for the UK.
Last year CGI won a £78m hosting tower contract with the Ministry of Justice.
For the first quarter, the firm's pipeline of contracts was $4.3bn (£2.9bn), double that of the same quarter last year. Michael Roach, CGI chief executive, said this reflects "improving market conditions".
According to CGI, it is the fifth-largest IT company in the world. The firm employs 68,000 people globally. ®