Although street youth are at increased risk of lifetime pregnancy involvement (LPI), or ever becoming or getting someone pregnant, no reports to date describe the epidemiology of LPI among systematically sampled street youth from multiple cities outside of North America. The purpose of our assessment was to describe the prevalence of and risk factors associated with LPI among street youth from three Ukrainian cities. We used modified time-location sampling to conduct a cross-sectional assessment in Odesa, Kyiv, and Donetsk that included citywide mapping of 91 public venue locations frequented by street youth, random selection of 74 sites, and interviewing all eligible and consenting street youth aged 15-24 years found at sampled sites (n=929). Characteristics of youth and prevalence of LPI overall and by demographic, social, sexual, and substance use risk factors, were estimated separately for males and females. Adjusted odds ratios (AORs) were calculated with multivariable logistic regression and effect modification by gender was examined. Most (96.6%) eligible youth consented to participate. LPI was reported for 41.7% of females (93/223) and 23.5% of males (166/706). For females, LPI was significantly elevated and highest (970%) among those initiating sexual activity at ≤12 years and for those reporting lifetime anal sex and exchanging sex for goods. For males, LPI was significantly elevated and highest (940%) among those who reported lifetime anal sex and history of a sexually transmitted infection. Overall, risk factors associated with LPI were similar for females and males. Among the total sample (females and males combined), significant independent risk factors with AORs ≥2.5 included female gender, being aged 20-24 years, having five to six total adverse childhood experiences, initiating sex at age ≤12 or 13-14 years, lifetime anal sex, most recent sex act unprotected, and lifetime exchange of sex for goods. Among street youth with LPI (n=259), the most recent LPI event was reported to be unintended by 63.3% and to have ended in abortion by 43.2%. In conclusion, our assessment documented high rates of LPI among Ukrainian street youth who, given the potential for negative outcomes and the challenges of raising a child on the streets, are in need of community-based pregnancy prevention programs and services. Promising preventive strategies are discussed, which are likely applicable to other urban populations of street-based youth as well.