Objective: To examine the severity, frequency, monthly variability and grouping of some common epidemics and its relation to hygienic conditions and life style of the people in Karachi., Methods: This ecological study was conducted from 2006 to 2009. Data was obtained from five different localities of Karachi. In each area, physician clinics were selected and questionnaire forms filled by professionals at the clinics, regarding health problems of patients. Multivariate analyses were used to summarize the data, for comparison and grouping the spread of epidemics., Results: The severity of different epidemics varied among months and localities. The effective diseases potential areas with decreasing order were: Lines Area, Korangi, Malir, Metroville and Maymar. In all these areas cough, allergy, asthma, flu, fever and skin rashes were the widely distributed epidemics while the prevalence of other six epidemics prevailed to a lesser extent. Lines Area/Korangi and Malir/Metroville differed considerably with respect to prevalence of epidemics (P < 0.05) into a lesser, while Gulshan-e-Maymar was significantly different (P < 0.001) from the other four areas. Among four distinct groups i.e. 1) allergy/cough, 2) asthma/flu, 3) fever/skin rashes, 4) bronchitis, malaria, typhoid, diarrhoea, rhinitis and sinusitis, the first three groups were widely distributed., Conclusion: January was the most crucial month with highest number of patients. Certain epidemics were parallel in different areas with almost similar population size. Multivariate analysis disclosed the four distinct groups of epidemics in which first three groups were widely distributed.