This study was conducted in a field located at Department of Biology/College of Sciences/University of Baghdad, from the period  between  the Mid of August to the second half  of October 2015, in order to study the population density of cowpea leaf miner on California Ramshorn cowpea and local varieties (Bayader) and their natural enemies.  The result showed fluctuation of the population density for Liriomyza trifolii on the American variety. Two peaks for population density were shown and  the second was higher than the first. The highest population density was 6.5 leaf miner/ leaf while the lowest was 0.7 leaf miner/leaf at the beginning of sampling. For the local variety, three peaks were recorded. The first was the highest with 2.61leaf miner/leaf and the lowest was 0.2 leaf miner/leaf. Population density of insect was higher on American variety has higherthan the local variety in its protein content which reached to 24.3%. Two hymenopteran parasites Pediobius matallicus and Diglyphus isaaea belong to the family Eulophidae were recorded on L. trifolii. This study, the first was conducted on the leaf miner on this host plant.