Gaps remain in understanding whether family planning (FP) programs can change urban women's FP behaviors. Even less is known about what works among poor urban women. This article presents results of the impact evaluation of the Nigerian Urban Reproductive Health Initiative (NURHI). Findings are based on recently collected longitudinal data from women and facilities in six cities in Nigeria. Over the four‐year follow‐up period, there was an increase of about ten percentage points in modern method use. Impact evaluation analyses using fixed‐effects regression methods indicate that both demand‐ and supply‐side program activities increased modern method use. Radio, television, community events, and living near program‐enrolled health facilities all significantly increased modern method use or were related to a desire for no more children among all women and among poor women. Results are discussed with an eye toward the design and scale‐up of future family planning programs in urban Nigeria and elsewhere in sub‐Saharan Africa.