BACKGROUND.: Breast cancer is the leading cause of cancer-related deaths in Latinas, chiefly because of later diagnosis. The time from screening to diagnosis is critical to optimizing cancer care, yet the efficacy of navigation in reducing it is insufficiently documented. Here, the authors evaluate a culturally sensitive patient navigation program to reduce the time to diagnosis and increase the proportions of women diagnosed within 30 days and 60 days. METHODS.: The authors analyzed 425 Latinas who had Breast Imaging Reporting and Data System (BI-RADS) radiologic abnormalities categorized as BI-RADS-3, BI-RADS-4, or BI-RADS-5 from July 2008 to January 2011. There were 217 women in the navigated group and 208 women in the control group. Women were navigated by locally trained navigators or were not navigated (data for this group were abstracted from charts). The Kaplan-Meier method, Cox proportional hazards regression, and logistic regression were used to determine differences between groups. RESULTS.: The time to diagnosis was shorter in the navigated group (mean, 32.5 days vs 44.6 days in the control group; hazard ratio, 1.32; P = .007). Stratified analysis revealed that navigation significantly shortened the time to diagnosis among women who had BI-RADS-3 radiologic abnormalities (mean, 21.3 days vs 63.0 days; hazard ratio, 2.42; P < .001) but not among those who had BI-RADS-4 or BI-RADS-5 radiologic abnormalities (mean, 37.6 days vs 36.9 days; hazard ratio, 0.98; P = .989). Timely diagnosis occurred more frequently among navigated Latinas (within 30 days: 67.3% vs 57.7%; P = .045; within 60 days: 86.2% vs 78.4%; P = .023). This was driven by the BI-RADS-3 strata (within 30 days: 83.6% vs 50%; P < .001; within 60 days: 94.5% vs 67.2%; P < .001). A lack of missed appointments was associated with timely diagnosis. CONCLUSIONS.: Patient-centered navigation to assist Latina women with abnormal screening mammograms appeared to reduced the time to diagnosis and increase rates of timely diagnosis overall. However, in stratified analyses, only navigated Latinas with an initial BI-RADS-3 screen benefited, probably because of a reduction in missed diagnostic appointments.