Pig-fattening on smaller conventional farms represents a substantial proportion of Slovenian pig farming. The production results achieved in fattening are extremely important. In this diploma thesis, I monitor the impact of the diet, as well as certain environmental influences on the growth and the characteristics of carcasses. We monitored fattening pigs and the impacts on their weight at the Zaverl farm. On the farm, we produce some of the feedingstuffs ourselves and we mix compound feedingstuffs for all categories of fattening pigs. We analysed the content of nutrients and minerals in individual feedingstuffs, calculated compound feedingstuffs and analysed them. We also examined the particle size in prepared feedingstuffs. The results showed that the housing, the size of the stalls and the temperature in the pigsty were suitable and did not have a significant impact on the results of fattening. We found that the particle size and the composition of compound feedingstuffs were appropriate and that they were composed according to the recommendations for pig-fattening in individual categories. According to Danish recommendations, feedingstuffs could be more finely grinded, which might give us better conversion. We can conclude that none of the impacts on fattening that we were monitoring had any significant effect on the production results. The average gains achieved were 824 g/day, which is higher than envisaged in the Slovenian Breeding Programme for Farms. The pigs also achieved a good lean meat percentage, 60% on average, which classified most of them in class S. The results we got will be very helpful for the future work on our farm, because they allow us to improve our production goals.