The role of reinfection and the importance of partner treatment were added to a pharmacoeconomic model for the analysis of a GP-based opportunistic screening programme for Chlamydia trachomatis (CT) in sexually active women in Amsterdam. A favourable cost-effectiveness was found for partner treatment. Partner treatment was cost saving and overall net costs per major outcome averted by the screening programme were reduced by 40% or more due to partner treatment. From a pharmacoeconomic point of view partner treatment should be routinely provided in the framework of a CT screening programme for Amsterdam women.