INTRODUCTION Reaction time is the interval time between the presentation of a stimulus and the initiation of the muscular response to that stimulus. A primary factor affecting a response is the number of possible stimuli, each requiring their own response, that are presented. Reaction time is an indirect index of processing capabilities of the central nervous system. Purpose: The present study was carried out to determine if there is any influence of body mass index (BMI) on simple reaction time (SRT) in healthy young male sportspersons. MATERIALS AND METHODS Subjects: This study was carried out in the district of Murshidabad in West Bengal, India with 30 College students of age group 22 to 25 years, who were participating Football and Cricket games in regular basis. Group Design: The subjects were divided into 2 groups each of them consisted with 15 subjects, that is, those who were participating in the game of Football (FG) and those who were participating in the game of Cricket (CG) in regular basis and had participated minimum state level in respective games and sports. The height (in Cm.) and weight (in Kg.) of the subjects were recorded and the BMI was calculated accordingly. The simple reaction time of the subjects were measured with the help of Ruler Drop Test. Statistical Design: The mean and s.d. of weight, height, BMI and reaction time of the subjects were calculated by using simple descriptive statistical formula. Then relationship between BMI and Simple Reaction Time was calculated by using Pearson Correlation Coefficient formula. Again the comparison between two groups regarding BMI and reaction time was done by using t-test. RESULTS AND DISCUSSION Findings show that the mean height and weight of Football group (FG) are greater than the mean height and weight of Cricket group (CG) respectively. It is also found that mean and s.d. of BMI of FG are 22.54 Kg/m2 and 0.7679 Kg/m2 respectively and for CG these are 22.167 Kg/m2 and 1.1273 Kg/m2 respectively. At the same time, mean and s.d. of Simple Reaction Time for CG are 0.198 sec. and 0.0086 sec. respectively and the same for FG are 0.2040 sec. and 0.0051 sec. respectively. ANALYSIS AND INTERPRETATION It is found that in case of footballers correlation coefficient between BMI and simple reaction time is negative as well as low. Which depicts that there is no relationship between BMI and simple reaction time in case of football players, as well as high BMIs are showing low simple reaction time also, which is unpredictable. At the same time, cricket players are showing positive high relationship between BMI and simple reaction time. Which means that, in case of Cricket group, high BMI indicates high in reaction and vice versa. But it is to mention that, most of the subjects show perfect or appropriate BMI as per their height and weight, and they are showing average performance in simple reaction time without major influence of height and weight. t-test between BMI of FG and CG shows no significant difference between the two groups. At the same time t-test is showing significant difference between two groups so far as simple reaction time is concerned. CONCLUSION Cricket players are showing more significant relationship between BMI and Simple Reaction time in comparison to Football players of same level. At the same time, as mean BMI of CG is low, they show less Reaction time on an average in comparison to FG. Result shows that there is no significant difference between FH and CH in respect of BMI, but there exists a significant difference between FG and CG so far as Simple Reaction time is concerned. It is to mention that CG take less time to react in a known visual stimulus of falling ruler at the time of ‘Ruler drop test’