Description: Giardiosis is a parasitic disease prevalent worldwide that affects humans, domestic and wild animals and can be responsible for chronic diarrhoea. Diarrhoea started in the time of wintering at the stables of the Institute for the Health Care of Pigs. Two sows (Krsko polje breed), and four piglets aged two months (the Krsko polje breed) were affected. Rectal smears were sent for bacteriological examination. Faecal samples were examined by microscopy using the SAF method for concentrating protozoa and by direct immunofluorescence (DIF). No pathogenic bacteria were isolated at the first bacteriological examination but the second examination confirmed the presence of Campylobacter coli. Giardia sp. was detected by SAF and DIF at the first test. The pigs were treated with Monil 5 percentage (Pliva d.d., Croatia) with 20 mg/kg albendazole, per os, once daily, for 3 days. After 3 days therapy the diarrhoea stopped and the pigs were clinically healthy and remained without diarrhoea for the next four months. Seven days, ten days and eleven days after the treatment all tested samples were negative by SAF and DIF