Abstract: ASLNP wetlands are important feeding sites of lesser flamingos (Phoeniconaias minor). It is located in the Great Rift Valley. Flamingos constitute the major content of the bulk of lakes. However, studies to determine food preferences of flamingoes in Ethiopia using crop content analyses are lacking. The analysis of diets examined during 2011-13 at two major feeding sites of Lakes Abijata and Chitu. Bacillariophyceae (diatoms) and Cyanophyceae (blue green algae) constituted the main diet of lesser flamingos in Lake Abijata. Nine diatom genera were identified in the crop contents of the bird. Diatoms had the highest percentage abundance (90.1-95.5%). These were followed by sand particles and detritus (3.9-9.16%) and Cyanophytes (0.23-0.87%) and Navicula was always the most common genus and accounted for 94.17 % of the average total algal density. The analysis of diet from the two flamingos in Lake Chitu had clearly shown that only one species Arthrospira fusiformis was dominating. There were insignificant variations on morphometric features of birds within and between lake birds. The distribution and abundance of flamingos are related to food supply. Thus, changes in the numbers of flamingos at a particular lake during the year and between years may reflect fluctuations in the availability of food supply. Lesser flamingos are specialized feeding on diatoms in Lake Abijata and Spirulina, in Lake Chitu. Presently, there is no effective protection of flamingo feeding areas or enforcement of laws protecting the bird.