Investigations were carried out during the summer season (March-June 2012) to observe the quality of indoor air by monitoring the levels of some selected air pollutants at 15 different houses covering the urban areas of Lucknow City. Concentrations of CO2, CO, PM10, PM2.5, SO2 and NO2 were monitored indoors and outdoors simultaneously and I/O ratios were calculated. Regression analysis for I/O relationship was performed to assess the contribution of outdoor sources to indoor air quality. Air Quality Index (AQI) for indoor air was also calculated to have an idea about the quality of indoor air and their health effects. In collaboration with the medical college doctors of the city, we surveyed 197 persons to find out different diseases/symptoms being faced due to indoor air pollution. Results of the study revealed that the average levels of PM10 and PM2.5 were above the permissible limits laid by WHO at densely populated and roadside sites with 189μg/m(3) (PM2.5 76μg/m(3)) and 226μg/m(3) (PM2.5 91μg/m(3)) respectively. Correlation analysis showed positive results. At sites like Alambagh and Chowk, the indoor AQI range was alarming with the values of 302 and 209. Survey results also showed that 46% of urban people suffered from acute respiratory infections like bronchial asthma, headache, depression and dizziness and these people were mostly from Roadside colonies.