This study was performed on 4 Balady chicken farms in Dakahlia Province during the period from November, 2008 to April 2009. These farms suffered from difficult respiration, diarrhea and decrease body weight. Other birds suffered from swollen crop and regurgitate of slimy foul smelling food. These farms in (12.000, 10.000, 8.000 and 4.000) with (3%, 1%, 1.5% and 0.5%) mortality rate respectively. Their ages ranged from 25 to 120 days. Twenty five birds were taken from each farm for mycological and pathological examination. Macroscopically small garish white or yellowish fragil nodules of 1mm diameter were noticed in lung, air sacs, heart, liver, intestine, proventriculus and skeletal muscles. Mycological examination revealed the isolation of Aspergillus species which identified by biochemical reaction as Aspergillus (flavus – niger, ochraceous and fumigatus). Histopathologically, numerous caseated nodules were observed in the pulmonary tissues, the nodular with a caseous necrotic center surrounding with lymphocytes, macrophage and giant cells. Congestion and haemorrhage were noticed in the liver, heart, kidney along with septated hyphae of Aspergillus. Other birds revealed the isolation of Candida species were isolated from other birds which were identified as C. albicans (94) C. tropicalis (4), C. krusei (1) and C. parapsillosis (1).  These birds revealed thickening of the mucosa of the oesophages, crop, proventriculus and gizzard which initially covered by slimy material these lesions progressed to diphtheritic membrane which was difficult to be removed. Histopathologically, hyperplastic changes were reported in the cornified layers of the crop, oesophagus and proventriculus with degeneration and necrosis of the superficial mucosa. The necrotic mucosa were covered with diptheretic membrane with intensive leukocytic infiltration in submucosa. This study investigate the role of mycotic disease specially Aspergillus and Candida species in balady chicken farms during winter season. Increase of humidity with lowering of temperature during the period from November to April is the main predisposing factor for mycotic disease in balady chicken farm. In these studies the role of aspergillosis and candiasis in balady chickens farms was investigated. It was reported that increased humidity and low temperature (November to April) predispose for mycotic infection.