Introduction The aim of this study was to evaluate the economical and practical aspects of castration of piglets under general anaesthesia. Methods The present trial was performed between December 2002 and January 2003 in a 1,000 sow breeding unit in Croatia. Five groups of neonatal male pigs were formed and the animals castrated as follows: Group 1 (n=20): without anaesthesia, Group 2 (n=20): ketamin (10 mg/kg body mass [BM]) i.m. and acepromacin (2 mg/kg BM i.m.) neuroleptanalgesia, Group 3 (n=20): ketamin (10 mg/kg BM i.m.) and acepromacin (0.2 mg/kg BM i.m.) neuroleptanalgesia, Group 4 (n=20): ketamin (10 mg/kg BM i.m.) and azaperon (2 mg/kg BM i.m.) neuroleptanalgesia, Group 5 (n=20): non castrated. The following parameters were evaluated: A: duration of postoperative neuroleptanalgesia (Groups 2-4), B: wound healing (Groups 1-4), C: body mass of piglets on day of castration and on days 7, 14, 21, D: morbidity, E: mortality. Results Postoperative neuroleptanalgesia was significantly longer (p<0.01) in group 2 (28 +/- 9.4 minutes) compared to group 3 (13.6 +/- 3.1 minutes) and group 4 (10.3 +/- 1.3 minutes). Wound healing showed no significant differences between the groups. On the day of castration there were no significant body mass differences between the groups. At day 7 (the fourth day after castration) the piglets that were castrated in neuroleptanalgesia or were not castrated (group 5), showed significantly (p<0.05) higher masses compared to the animals that were castrated without neuroleptanalgesia. The mass-differences of piglets were less but still significant (p<0.05) at days 14 and 21. There was no significant difference in mortality and morbidity in the Group 1 compared to the groups 2-5. Conclusion Castrating piglets in general anaesthesia is emphasized.