OBJECTIVES: To assess whether the offspring of UK veterans of the first Gulf war are at increased risk of fetal death or congenital malformation. METHOD: This was a retrospective reproductive cohort study of UK Gulf war veterans and a demographically similar comparison group who were in service at the time but were not deployed to the Gulf. Reproductive history was collected by means of a validated postal questionnaire between 1998 and 2001. RESULTS: In all, 27 959 pregnancies reported by men and 861 pregnancies reported by women were conceived after the first Gulf war and before November 1997. The risk of reported miscarriage was higher among pregnancies fathered by Gulf war veterans than by non-Gulf war veterans (OR = 1.4, 95% CI: 1.3, 1.5). Stillbirth risk was similar in both groups. Male Gulf war veterans reported a higher proportion of offspring with any type of malformation than the comparison cohort (OR = 1.5, 95% CI: 1.3, 1.7). Examination by type of malformation revealed some evidence for increased risk of malformations of the genital system, urinary system (renal and urinary tract), and 'other' defects of the digestive system, musculo-skeletal system, and non-chromosomal (non-syndrome) anomalies. These associations were weakened when analyses were restricted to clinically confirmed conditions. There was little or no evidence of increased risk for other structural malformations, specific syndromes, and chromosomal anomalies. Among female veterans, no effect of Gulf war service was found on the risk of miscarriage. The numbers of stillbirths and malformations reported by women were too small to allow meaningful analyses. CONCLUSION: We found no evidence for a link between paternal deployment to the Gulf war and increased risk of stillbirth, chromosomal malformations, or congenital syndromes. Associations were found between fathers' service in the Gulf war and increased risk of miscarriage and less well-defined malformations, but these findings need to be interpreted with caution as such outcomes are susceptible to recall bias. The finding of a possible relationship with renal anomalies requires further investigation. There was no evidence of an association between risk of miscarriage and mothers' service in the gulf.