Background Indulgence in sexual multi-partnerships (SMP) intensifies risks to sexually transmitted infections including HIV. In Tanzania where HIV/AIDS is more prevalent among women than men and consistent condom use is low, identifying drivers to SMP is pertinent for scheming feasible HIV/AIDS interventions.

Objectives

1. To establish prevalence of SMP and

2. Identify women’s socio-demographic characteristics associated with SMP in Rufiji, Kilombero and Ulanga districts in Tanzania.

Methods Data were collected cross-sectionally in Rufiji, Kilombero and Ulanga districts in Tanzania in 2011 on 2,643 sexually active women ages 15+ years. We used Chi-square for testing association between SMP and each of the explanatory variables and finally used logistic regression for multivariate analysis.

Results Number of sexual partners reported ranged from 1 to 7, with 7.8% of the women reporting multiple partners (> 1) in the past year. Sexual multi-partnerships among women was more likely among those ever married than currently married (OR = 2.88, 95% CI 1.75–4.74), single than currently married (OR = 2.28, 95% CI 1.52–3.42) and Muslims than Christians (OR = 1.51, 95% CI 1.04–2.18). On the other hand, SMP was less likely among women who were older than younger (OR = 0.96, 95% CI 0.94–0.98), educated at primary level than uneducated (OR = 0.64, 95% CI 0.42–0.98) and educated at secondary/higher levels than uneducated (OR = 0.23, 95% CI 0.11–0.47), Ndengereko than Pogoro (OR = 0.43, 95% CI 0.20–0.93) and Ngoni than Pogoro (OR = 0.47, 95% CI 0.23–0.94) ethnic groups. District of residence and socioeconomic status were not significant.

Conclusion Sexual multi-partnerships is an extant risky behaviour among women in rural Tanzania and varies significantly by age, marital status, education, religion and ethnicity. HIV/AIDS control programmes in the country should take these variables into consideration in designing fruit-bearing interventions for a HIV-free world.