Herpes simplex virus type 2 (HSV-2) is considered as a major co-factor of both sexual transmission and acquisition of the human immunodeficiency virus (HIV). The HIV epidemic in Senegal is characterized by a remarkable and stable low prevalence. Whether HSV-2 may also constitute a possible co-factor favouring the spreading of HIV epidemic in Senegal is yet unknown. This prompted us to evaluate the HSV-2 seroprevalence in the sentinel population of pregnant women in Senegal. Two hundred and sixty pregnant women attending Roi Baudouin maternity in the capital city Dakar (n = 14; 135) and the antenatal clinic in Kaolack (n = 125), the third city of Senegal, were prospectively recruited between March and August 2003. Fifty-six women (22%) were positive for HSV-2 serology. The prevalence of HSV-2 seropositivity was higher in women living in Dakar (26%) than in those living in Kaolack (16%) (P < 0.01). Only two women from Dakar and two other from Kaolack were found to be HIV-1-infected. Our observations suggest a seemingly low seroprevalence of HSV-2 infection in adult women Senegal, comparable with those usually reported in Western countries. Further, epidemiological surveys are needed to confirm these results in the general population.