Abstract: This study presents results of a study on causes, effects and controls of variation orders in large building construction. The researcher developed a survey questionnaire. The questionnaire was distributed to all building contractors, grade A and B as well as building consultants. The survey questionnaire included four areas of study. The first included questions on the general market characteristics and general trend. The second included questions on the possible causes of variation orders. The third included questions on the possible outcomes of variations. The fourth included questions on the management control tools utilized for minimizing the problems of variation orders. Responses from 34 consultants and contractors working in the field of large building construction were analyzed. Analysis of data indicated that cost overruns due to variation orders were in the magnitude of 5-10% of the original contract value. Schedule overrun was reported <10% of the original contract duration. The study also concluded that the owner is the major source of variations and that most variations are civil and structural. Change of plans and material substitution are first causes of variation orders in large buildings.