As to achieve a desired tooth movement the bracket slot dimensions need to be accurate, if not the treatment would be compromised. Slot dimensions are a critical factor in orthodontic tooth movement. However very little is known about the accuracy of the slot dimensions of commercially available brackets. Aims and objectives: To evaluate slot dimensions of four different commercially available 0.022 slot MBT prescription brackets. Materials and Methods: 100 Upper right central incisor brackets from 4 different manufacturers(3M Unitek -Gemini 0.022, American orthodontics-Mini Masters 0.022, Chirpans orthodontics – Eco-plus 0.022, Modern orthodontics-Sapphire 0.022) were measured for slot depth and width using confocal microscope which gives a digital readout accurate upto 1 micron and the brackets were grossly examined for surface defects using microscopic images. Results: The slot sizes were oversized, or undersized ranging from 0.017 inches to 0.031 inches, none of the manufacturers brackets were dimensionally accurate, surface irregularities were more evident in sapphire and Eco-Plus bracket slots Conclusion: Slot dimensions are not accurate, which might directly and unintentionally affect the planned tooth movement.