We provide data on intrapopulation variation of life history traits of Boa constrictor occidentalis in the District of Pocho, Córdoba, Argentina. A total of 153 individuals were captured. The distribution of individuals among four size classes differed significantly among the five years of study. The proportion of mature individuals did not differ between sexes but it showed variation among years. Females were longer and heavier than males. The mean litter size of the species was 24 and there was a linear relationship between litter size and maternal snout-vent length. Most boas were captured during the dry season. There were no significant sex differences in the time of capture and air temperature in either the wet or the dry seasons. However, we found significant differences in the time of capture and air temperature between the seasons. The long-term monitoring of wild populations should be a priority for the development of conservation and management plans for this boid.