As Black Slavonian pig was forgotten and replaced by commercial hybrid pigs, after mid 1950s population declined drastically. Today’s population was founded from 46 sows and 6 boars in 1996 while currently consist of 1064 sows and 163 boars. Aim of this study was to evaluate the genetic structure and genetic variability in autochthonous Black Slavonian pig breed using pedigree. The quality of the pedigree information was evaluated by percentage of known ancestors, which was about 35.16%. Increase in pedigree completeness over the years is evident. Number of inbred Black Slavonian animals was 1695. Average inbreeding was 3.2%, with evident growth observed by year. Effective number of founders was 50.8 for males and 51.1 for females. Effective number of ancestors was, 35.8 for male and 34.8 for female animals, respectively. The proportion of the genes contributed to the reference population of males and females by the most important ancestor was 7.1% and 9.1%. The first 15 ancestors for males and 12 for females explained around 50% variability in the gene pool. Average effective population size via number of parents for the last 10 years of Black Slavonian pig is 189.2. In order to perform proper selection decisions, additional work should be done to increase the quality of pedigree data affecting the reliability of estimated parameters and genetic structure of the population.