The present study reports the result of knowledge, attitude and practice of mother towards vaccination and reasons of immunization's defaulting of children U5 years of age in one of the lowest immunization coverage areas in Abu-Ghraib district, Baghdad during the year 1992-1993. The mothers of children who did not start or did not complete vaccinating their children according to Iraqi schedule were inquired directly at home about the reasons of defaulting. The sample frame included 302 mothers of children of under five years old from two areas, the area of survey included four urban sectors (hay) and four rural ones each consist of three villages. A special questionnaire of two parts was employed. The first part provides general information and the characteristics of the respondents. In addition informations about the vaccination status were inquired about. The second part was mainly concerned with evaluation of the obstacles that might have interfered with delivery of vaccinatiorw services and assessment of the mother's knowledge, attitude and practices on immunization. The most important reason for not vaccinating the children was the obstacles the mothers faced either due to family causes (77% urban - 66% rural) or health centre activity causes (36% urban - 22% rural). Next of the reasons were lack of motivation (26% urban - 14% rural) , then lack of knowledge (23% urban - 7.7% rural). However, the mother response to leading questions resulting in higher emphasis on obstacles, 90% of the mothers said that crowdedness in the centre was the major obstacle followed by the cost of reaching the health centre specially among the rural mother (80%) and to lesser extent among urban mother (39%). Furthermore, almost half of mothers had visited the health centre more than one time to get vaccination for their children. One third of urban mothers thought that provision of milk might be a good incentive for vaccination while rural mother were not very much impressed by it. It is encouraging to know that only minority of both urban and rural mothers who did not believe in vaccination (0.8 - 1.8%) respectively. The study highlights the need to improve the accessibility to vaccination and proper monitoring of the coverage by the H.C. In addition the proper use of Television and mass media is advised as most of women (90%) have gained their knowledge about vaccination through these channels.