A bio-economic model including a computer program was developed where a large number of parameters can be modified to describe a great variety of production systems. Economic values for up to 27 traits can be calculated. Seasonal feeding is incorporated and protein requirement in addition to net energy may be taken into account when calculating feed requirement. Furthermore, the model allows for the evaluation of individual parts of the growth curve. The model was applied to the Czech Suffolk breed used in pure-breeding. The economic values (in Euro cent per ewe, per year and per genetic standard deviation of the trait) were: 9.9 for birth weight, -72.6 for mature weight, 142, 32.1 and 16.9 for growth rates till weaning, in rearing of breeding animals and in fattening, respectively, 19.9 and 101 for conception rate of female lambs and ewes, respectively, 690 for litter size per ewe lambing, 172 for productive lifetime of ewes, 402 and 503 for survival rate of lambs at lambing and till weaning, respectively, and 16.5 for fleece weight.