Background: Physical inactivity is a modifiable risk factor for obesity, diabetes, cardiovascular diseases, and certain types of cancer. Objectives: This study aimed to investigate the patterns and demographic correlates with physical activity among an urban population in Shiraz, Iran. Materials and Methods: This study was a population-based cross-sectional study with a multiple-stage sampling method of 700 subjects, all over 18 years old. Physical activity was assessed through the long version of the international physical activity questionnaire (IPAQ), using face-to-face interviews with last-week recall. Participants were categorized into inactive, moderate, and intense activity categories. For data analysis, SPSS version 19 was used. Student's t-test and one-way ANOVA were also performed. Results: Based on the three activity categories established by the IPAQ, 14.3% of Shiraz adults were inactive, 44.5% were active, and 41.2% had a high level of activity, but > 67.6% of the sample did not engage in any type of vigorous-intensity physical activity lasting for at least 10 minutes. Males and young people participated in more vigorous activity compared to females and older people. Married and highly educated people were more likely to demonstrate higher levels of physical activity during leisure time. Conclusions: According to the results of this study, there is a need to promote various forms of physical activity, with special attention to leisure-time activities and vigorous-intensity physical activity, across both genders and all age groups, especially in jobless and poorly educated individuals.