Some microdimatic variables were examined in a poultry house at Dakahlia prov ince. It was clear from the results that the accumulation of carbon dioxide and ammo nia inside the poultry house were from the 1st to 7th week of examination( 1240I l l 20 - 3740 / 3400 p.p.m) and (35/ 17-75 / 65 p.p.m) in case of carbon dioxide and ammonia respectivel y. although the accumulation was higher in summer than in autumn months. The highest microorganism carrying particles were observed at the 4th week where the R.H% was 82 and temperature of 30°c & 26oc. There tuas a marked relationship between Eime1ia oocyst count and temperature with pH o..f the litter, where it reached the highest count at temperature of 29°C and pH q.f 7.6 (1200) .in summer season and (1600) in autumn one. The coliform count allover the period of examination in autumn weeks was lesser than that in summer weeks. There was a correlation between the bod y gain of the bird s and temperature with humidit y as a microdimaii c variable.