A bioeconomic model simulating the lifetime production of a group of purchased gilts and their progeny was developed to estimate economic weights of traits in pig breeding. For the Czech situation, the following marginal economic values were calculated (in Czech crowns per unit of the trait): 30.5 for lifetime daily gain (ADG, in g/day), 1038 for lean meat content (LM, in %), 2975 for valuable cuts (WVC, in kg), 2040 for number of piglets bom alive (NBA, in piglets per litter), — 560 for energy intake per kg gain (in MJ ME/kg), 34.7 for conception rate (in %) and – 119 for culling rate of sows (in %). Taking into account the intended use of breeds, the following economic weights for traits in the breeding objective were estimated: ADG 3.5, WVC 342, NBA 477 for Large White; ADG 2.4, WVC 238, NBA 290 for Landrace, and ADG 8.3, WVC 812 for sire breeds. A sensitivity analysis showed that the relative values of traits might change in future. Expecting an increase in costs, higher economic weights should be given to reproduction and growth traits; expecting a decrease in meat price, production traits will be more important. © 2003 Elsevier B.V All rights reserved.