The purpose of this study was to evaluate the impact of the individual services offered via a workplace lactation program of one large public-sector employer on the duration of any breastfeeding and exclusive breastfeeding. Exclusive breastfeeding was defined as exclusive feeding of human milk for the milk feeding. A cross-sectional mailed survey approach was used. The sample (n = 128) consisted of women who had used at least one component of the lactation program in the past 3 years and who were still employed at the same organization when data were collected. Descriptive statistics included frequency distributions and contingency table analysis. Chi-square analysis was used for comparison of groups, and both analysis of variance (ANOVA) and univariate analysis of variance from a general linear model were used for comparison of means. The survey respondents were primarily older, white, married, well-educated, high-income women. More of the women who received each lactation program service were exclusively breastfeeding at 6 months of infant age in all categories of services, with significant differences in the categories of telephone support and return to work consultation. After adjusting for race and work status, logistic regression analysis showed the number of services received was positively related to exclusive breastfeeding at 6 months and participation in a return to work consultation was positively related to any breastfeeding at 6 months. The study demonstrated that the workplace lactation program had a positive impact on duration of breastfeeding for the women who participated. Participation in the telephone support and return to work consultation services, and the total number of services used were related to longer duration of exclusive and/or any breastfeeding.