Plasma androgen and prolactin levels were determined by radioimmunoassay in 9 male crossbred (3/4 wild, 1/4 domestic) boars between 4 and 26 months of age. The boars were kept in outdoor enclosures. Androgen concentrations showed a clear seasonal pattern with the highest level in November; 6.48±1.31 ng/ml and 13.44±1.39 ng/ml during the first and second year of life, respectively. Data for the two years studied well demonstrated age-related androgen level variations with an elevation between 5 and 7 month of life (1.74±0.18 ng/ml) and maximum in 13 month-old boars (6.48±1.31 ng/ml). The prolactin level was low at 4 months of age (0.57±0.22 ng/ml), increased until 9-10 months (24.45±2.04 ng/ml) and decreased thereafter. Higher values were observed during the summer months (24.33±2.07 ng/ml) as compared with the rest of the year. It seems that there is a seasonal and age interaction in androgen concentrations with a predominance of season-related changes.