Our objective was to evaluate diagnostic tools for the detection of Inclusion Body Disease (IBD) in bold snakes. The aetiology of IBD is unknown, and the disease has non-specific clinical signs, hence there is a need for a clinically-applicable, specific diagnostic method. We examined blood smears and liver biopsies from 26 bold snakes (17 boas and nine pythons; some of which were suspected of having IBD) for the presence of characteristic inclusion bodies. We used haematology, histology and electron microscopy to characterise samples as IBD-positive or -negative. Our results indicate that examination of a simple blood smear is sufficient to diagnose IBD in boas. Inclusion bodies in lymphocytes, erythrocytes and thrombocytes were observed. In both, boas and pythons, we detected inclusion bodies within hepatocytes. We demonstrated also that IBD was more common in boas than in pythons: only samples from two Ball Pythons (Python regius) tested positive, whereas no other Pythonidae were positive. We consider that blood smears represents a rapid, non-invasive technique for detection of IBD.