In this study, academic achievement was compared between regular andrnextension students. And also an attempt was made to assess the effect of certainrnfactors (independent variables) namely years break in study, high school gradesrn(ESLCE GPA), age on entry, sex and marital status upon the dependent variablern(academic achievement). To serve this purpose 343 students (203 regular andrn140 extension) who entered the Addis Ababa Commercial College (AACC) inrn1990/91 and 1991192 academic years were selected as a sample. Among thernregular students 116 were males aiul 87 were females. Out of the extensionrnentrants 63 were males and 77 were females. Cumulative Grade Point Averagern(CGPA) was used to compare the academic achievement status of regular andrnextension entrants. Student's personal files were consulted to obtain datarnpertaining to [he independent variables considered in this study. In addition,rnstructured interview was conducted with the instructors teaching both regularrnand extension classes, counselors and a co-ordinator of the continuing educationrnprogram at the MCC. The interview was aimed at getting information aboutrnthe position of regular and extension students with respect to their academicrnachievement, the academic problems of the two groups of students and the statusrnof guidance and counseling. Data were analyzed using a t-test and analysis ofrnvariance. The results of these tests indicated that: 1) regular and extensionrnstudents at the M CC dijJer significantly interms of their academic achievement,'rn(2) years break in study, high school grades (ESLCE GPA), age on entry andrnmarital status are significant as factors affecting academic achievement ofrnstudents,' (3 ) gender has no significant effect on academic achievement