The　problem　of　finding　intrinsic　parameters　of　a　camera　is　extremely　important　for　practical　applications.　In　this　paper,　we　present　an　approach　for　automatic　estimation　of　intrinsic　parameters　from　images　by　using　the　vanishing　points　in　orthogonal　directions.　Firstly,　image　lines　are　extracted　and　clustered　into　groups　corresponding　to　three　dominant　vanishing　points.　Secondly,　the　intrinsic　parameters　of　the　camera　are　determined　by　using　the　vanishing　points　in　each　image.　The　rotation　matrix　of　the　projection　matrix　is　computed　from　the　vanishing　points　and　image　edges　while　the　translation　matrix　is　obtained　with　additional　translation　motion　between　the　viewpoints.　Our　approach　does　not　need　any　prior　information　about　the　cameras　being　used.　Experiments　with　real　images　show　that　our　new　technique　is　robust　and　accurate.