Background and Objective: Cellulitis is an acute infection of cutaneous and subcutaneous tissue. Inaccurate treatment of cellulitis can cause important complications like abscess, myositis, osteomyelitis, bacteremia, septicemia, endocarditis, meningitis, and other complications and can lead to death. The aim of this study was to assess the epidemiology of cellulitis that result in complication among in-patients in infectious diseases ward.
Subjects and Methods: The population  of the study  included all  patients  admitted  with  final diagnosis of cellulitis in the infectious ward  of  Ahvaz  Razi hospital  during 2001-2003.Regarding variables under study (age, sex, occupation and underlying diseases), the relation between complications caused in relation to each of the complications and these variables were assessed. Data were analyzed by SPSS-15 and using descriptive and analytical statistical methods and chi-squared test with P<0.05 was considered significant.
Results: In this study, of totally 230 cases, 150 cases were studied. The results were including: 25 % of total patients encountered with complications, 18.7% of complications were abscess, 3.3% of complications were necrotizing faciiatis, 0.7% of complications were sepsis and 2.7% of complications were osteomyelitis.  There was not significant relationship between total cellulitis complications with variables such as:age, sex, job, immunosuppressive disease, consumption immunosuppressive drugs and narcotics injection in patient while there was significant relation between total complications and total incoming trauma, and bite history.   
Conclusion: The significant relationship between complications of cellutitis and the two variables of trauma and history of animal biting suggest, for better management of these patients, more careful assessment is warranted.