High environmental temperature during summer season is stressful and has adverse effect on productive and reproductive performance of layers. The present study was conducted at the Poultry Experiment Station, University of Agriculture, Faisalabad (Pakistan) on 300 White Leghorn (Euribrid). Three units under each of the following 4 heat combating systems and the control were maintained under cage housing in the similar and equal sized (7.6 x 7.0 meters) separate rooms. The body weight of layers was observed to decrease progressively during the first 4 weeks in all the experimental groups. This decrease was more severe in case of control birds followed by those under time limit feeding and ascorbic acid supplementation systems. Feed consumption of the birds, in general, showed a progressive decline during the first 4-5 weeks of the study in all the groups. The mean feed consumption of the birds under desert cooling and water sprinkling systems, apparently showed an increase over that of the control birds during he heat stress (HS) phase. The overall mean egg production of the layers during the first week was about 68 percent. Later on the birds on the whole could not adjust to the heat stress temperature and production suddenly dropped to about 66 percent that almost persisted with the production of eggs averaging about 65 percent. The overall mean egg weight of the layers under various groups exhibited a decline during the 2nd week of the experiment. However, subsequently the egg weight remained almost constant during the HS phase. After the HS phase the egg mass out-put during period V was significantly higher than that for period IV only because of a significant increase in egg weight but not the level of production. Feed efficiency of the layers in terms of feed consumed per dozen eggs exhibited almost a constant trend. Feed efficiency in terms of feed intake in kg per kg egg mass output showed, in general similar trend after the first week.