The individual and combined effects of AF (100 ppb) and T-2 toxin (1 ppm) were studied in turkey poults by feeding the toxins from 0 to 13 weeks of age. There was significant reduction in the body weight gain in the toxin fed groups compared to the control. Significant reduction in PCV, Hb and TEC values, hypoproteinaemia, hypoalbuminemia, hypoglobulinaemia, hypoglycaemia, increased serum AST, ALT, ALP, lipase, uric acid, creatinine, hypocalcaemia and hypophosphotaemia were observed in the toxin fed birds. The lipid profile revealed hypotriglyceridaemia, hypocholesterolaemia, decreased HDL, LDL and VLDL in the toxin fed birds. Increased liver lipid peroxidation, decreased GSH, GPx, SOD and CAT levels and increased GST level were observed in the toxin fed groups. The HI titre to NDV and lymphocyte SI were decreased in the toxin treated groups. Relative spleen weights were decreased in the toxin fed groups. Grossly, AF fed birds showed enlarged yellowish discoloured liver in AF and T-2 toxicities, oral and hepatic lesions in T-2 fed group and shrunken pale yellow liver in combined group at 13th week. The AF-T-2 treated birds were poor in condition. Microscopically, the toxin fed birds revealed mild diffuse vacuolar degeneration of hepatocytes, biliary hyperplasia, catarrhal cholangitis, periportal mononuclear cell (MNC) infiltration, megalocytosis, periductal fibrosis, microgranuloma and adenomatous areas in the liver, mild renal tubular epithelial cell degeneration, shortening and fusion of proventriculus villi, focal necrosis, catarrhal changes of mucosal epithelium and degeneration of crypts. The gizzard showed distension of glands, reduced secretion, hyperplastic changes, mild interglandular fibroplasia with focal cystic changes. The bursa of Fabricius revealed medullary oedema, cortico-medullary lymphoid cell depletion, medullary lymphoid necrosis, glandular transformation, reticulum cell hyperplasia and fibroplasia. The spleen revealed mild to moderate depletion of lymphoid cells, lymphocytolysis, heterophilic infiltration and reticulum cell hyperplasia. The thymus revealed starry sky appearance in the cortex. The caecal tonsils revealed mild to moderate lymphoid cell depletion in the follicles and in diffuse lymphoid tissue. The Harderian gland showed mild plasma cell depletion. Pancreas revealed mild acinar cell degeneration. Diphtheritic glossitis with bacterial colonies was observed in T-2 intoxication. In the Pasteurella multocida – mycotoxin interaction studies, significant decrease in the ELISA titre to Pasteurella multocida in turkey poults was observed in mycotoxin treated groups. Three hours after challenge, all the poults except vaccinated control birds were depressed and showed respiratory signs and cyanosis. Mortality of the poults started 7 hours post challenge which followed till 22 hours. One bird in the vaccinated control died. Grossly, all visceral organs revealed congestion and serosal haemorrhages in the duodenum, congestion, oedema and haemorrhages in the trachea and lungs. Petechial haemorrhages in pericardium of the heart, enlargement of liver and spleen, multiple small necrotic foci in the liver and spleen were also observed. The histopathological changes included serofibrinous pneumonia, necrotic hepatitis, splenitis, while bursa of Fabricius, spleen, thymus and caecal tonsils revealed lymphoid cell depletion in almost all the groups. Conclusions: The study revealed that lower levels of AF (100 ppb) and T-2 (1 ppm) could affect the performance and health of turkey poults. The toxin predisposed even the vaccinated birds to pasteurellosis and caused 100 per cent mortality on challenge.