introduction: since the first alert calls from the world health assembly the last century, low rates of incidence and duration of breastfeeding are recognized as a public health problem. objective: to characterize the practice of partial and exclusive breastfeeding in the department of caldas in the year 2010 according to social-demographic variables. materials and methods: descriptive cross-section study in a 1,316 resident mothers probabilistic sampling living in the urban area (70.5%) and rural (29.5%) of 26 municipalities of caldas, excluding manizales. the sample was calculated from a pilot test in 200 homes in the urban area in the south centre sub-region of caldas, with which an average duration of exclusive breastfeeding for 4.7±2,4 months was found. with this data the sample for finite populations was calculated, with a 3% error rate and a 95% confidence rate from the total number of live births in caldas in 2009. results: the median duration of exclusive maternal breastfeeding in caldas was three months. it was inferior in 1.2 months to the goal proposed by the colombian national food and nutritional security plan for exclusive mother breastfeeding established in 4.2 months, but it was superior to the national goal established in 1.2 months (ensin 2010). the median of partial mother breastfeeding or with other food supply was 4 months. conclusion: the municipalities with the highest median percentile of exclusive breastfeeding were chinchiná and marulanda and those with the lowest median were pácora, la merced and belalcázar.