Insomnia is a condition that affects an individual by inability to get sufficient quality sleep or problem in maintaining sleep that is important for healthy functioning, performance and wellbeing. There is very scarce data regarding insomnia and its relation with different diseases. The present study was aimed to find out the association of insomnia with comorbidities among patients visiting Tertiary Care Hospitals, Lahore. A cross sectional study was conducted from May 2019 to September 2019 in Tertiary Care Hospitals district Lahore. Interviews were conducted by researchers to collect data through Pre-Tested Questionnaire. Informed consent was first taken from all participants. Data were analyzed by using Chi-square to find out the association of insomnia with comorbidities through SPSS version 25.0. Thousand (n=1000) patients suffering from different diseases randomly selected to participate, of which 43.6% were male and 56.4% were female. Results of present study revealed that association of insomnia with the diseases such as cardiovascular diseases (p=0.05), diabetes mellitus m(p=0.001), gastrointestinal problems (p=0.034), premenstrual syndrome (p=0.00), joint pains (p=0.01) and prostate cancer (p=0.01) was found to be significant. While an insignificant association of insomnia was noticed with hypertension (p=0.850), hearing impairments (p=1.22), COPD (p=0.288). It was concluded that insomnia was most commonly present in the patients of cardiovascular diseases, diabetes mellitus, premenstrual syndrome, gastro-intestinal problems, joint pains and prostate cancer.