Bangladesh is one of the most densely populated countries in the world having only 12.5 decimals per capita arable land. With the growing population, and their increasing needs in various sectors, land use patterns are changing over time with a losing of arable land. However, there is no reliable information is available till now on the rate of conversion of agricultural land. Therefore, this was undertaken to estimate the present land use pattern and to calculate the changes in land use in agricultural and non-agricultural field over time by using aerial photographs of Trishal and Fulbaria Upazilas. Two series of aerial photographs of both Upazilas from 1983 and 2000 at scales of 1:40,000 and 1:25,000, respectively, were studied. Land uses category was calculated by random line drawing method on effective areas of aerial photograph. In 1983, Total agricultural and non-agricultural land of Trishal Upazila were found 29505 and 4095 ha accounting 87.81 and 12.19% of total land area, respectively. It was estimated 35611 and 4258 ha accounting 89.32% and 10.68% of total land area, respectively, in Fulbaria Upazila for the same year. However, land coverage under agriculture and non-agriculture sector in 2000 was estimated 25960 and 7640 ha accounting 77.26% and 22.74% of total land area, respectively in Trishal Upazila, and 31976 and 7894 ha accounting 80.20% and 19.80% of total land area, respectively, in Fulbaria Upazila. An amount of about 3545 and 3637 ha agricultural land was transformed into non-agricultural land in Trishal and Fulbaria Upazila, respectively, within a period of 17 years. Therefore, the rate of decreasing agricultural land to non agricultural land in Trishal and Fulbaria Upazila was 0.621 and 0.536% /annum or 208.5 and 213.9 ha/annum, respectively. Land use analysis shows that conversion of agricultural land into settlement, transport network and water body contributed 88.07, 5.3 and 6.63% of the land loss in Trishal Upazila and 98.45, 1.3 and 0.12% of the land loss in Fulbaria Upazila. If the similar trends in loss of agricultural land remain, there will be no land available for cultivation after around 200 years. Therefore, it is very crying need for the country to make a land use policy for food security of the rapidly growing population.