This paper predicts the probability of failure or short and long columns of square reinforced concrete for deterministic and probabilistic loads. The effect of various parameters; width, length of column, effective length coefficient, percentage of steel, axial load, grade of concrete and random numbers; on the probability of failure of the column is studied. The material, geometric parameters and the load are treated as probabilistic. The results for short columns show that the rate of decrease of probability of failure is a maximum with increase in width, while it increased to a maximum with increase in loads, whereas for long columns the length of column had the predominant effect.