In 2014 and 2015 growing seasons, tomato seedlings cv. Alisa were transplanted on 15th February and 6th March and harvested on 13th May and 25th May, respectively in a private farm, Belbeis district, Sharkia Governorate, Egypt and subjected to the following post-harvest treatments in Post-harvest Laboratory, Hort. Dept. Fac. Agric., Zagazig University: 1) stored in open air (control); 2) stored in active modified atmosphere (AMA) with 3% O2+3% CO2 ; 3) AMA with 5% O2+3% CO2 ; 4) AMA with 5% O2+5% CO2 and 5) AMA with 7% O2+ 5% CO2 . Fruits of all treatments were stored for 35 days at 10±1ºC and 90-95% relative humidity (RH). Samples of each treatment were randomly taken at 7 days intervals to evaluate the effect of cold storage periods and the tested (AMA) treatments on fruit quality. After each cold storage period, some of these fruits were kept for 5 days in both seasons under conditions of 20ºC and 60-70% RH to detect the effect of treatments on shelf life. The tested active modified atmosphere (AMA) treatments tended to increase fruit firmness and vitam. C content as compared with the control during both cold storage and shelf life periods. On the contrary, AMA treatments tended to decrease fruit weight losses, fruit decay, TSS and lycopene content during both cold storage and shelf life periods. The advance of storage period from zero up to 35 days caused progressive increments in fresh weight losses, fruit decay, lycopene and TSS content of the successive samples which taken during cold storage and shelf life as compared with the control. On the contrary, the advance in cold storage period depressed fruit firmness and fruit ascorbic acid contents