The purpose of this study is to assess the prescriptions pattern of penicillin and cephalosporin antibiotics among physicians at Sacred Heart Hospital Lantoro Abeokuta and determine their conformity with standard guidelines and principles of antibiotic use. It was a retrospective study involving data obtained from outpatient case notes that were prescribed with cephalosporin and penicillin antibiotics during the 6 months period of January to June 2010. A total of six hundred and fourteen (614) case notes were randomly selected and used for the study. One hundred and sixty seven (167) (27%) patients were of the age group 0 - 9 years, 31(5%) patients were aged 10 – 19 years and 226 (37%) patients were of age group 20 – 29 years . Four hundred and forty (440) (71.7%) patients were males while 174 (28.3%) patients were females. Among diagnosis studied were upper respiratory tract infection (URTI) 238 (38.8%) and lower respiratory tract infection (LRTI) (21.0%) (p = 0.00393) (p<0.05). There was no definite diagnosis (NDD) made in 37 (6.02%) cases.