The article analyses determinants influencing supply response in Slovenian pig production, in the period from January 1995 to December 2005. The two sets of models are developed. Both sets of models explain the quantity of pigs (live weight) sell on the market. The first set of models explains the quantity with own producer prices, whereas the second set of models is based on the gross margin. Standard Cobb- Douglas form of the profit function is used. The models are based on the ordinary least squares method and the corresponding tests. Based on the testing of various alternatives, including models, testing of statistical significance of individual lags of the exogenous variables, two models are developed. The model results reveal that the pig supply is influenced primarly by the own producer price, implying the achieved gross margins, and secondly by the price of maize, which also in Slovenia presents the main cost item in pig breeding. Other statistically significant determinants are the season and some unpredictable factors, such as the influence of the BSE disease and the crisis on the pork market. The elasticity of price values was low (about 0.3), as expected, thus confirming the thesis about the inelasticity of pig supply. Such results can be explained by a low level of producers adaptation to the market situation and by the presence of quasi-fixed expenses in pig production.