The Nerve Conduction Studies (NCS) are essential in the differential diagnosis of Guillain Barre syndrome (GBS). Finding the earliest and most common electrophysiological variables affected during early 0-3 days of illness promises to improve the patients' overall prognosis. Keeping these facts, we studied the various nerve conduction parameters in GBS patients to explore the extent and the earliest and most common parameters involved during illness. For these 30 diagnosed cases of GBS, the same numbers of normal healthy controls were taken for study. The parameters studied were the distal motor and sensory latency (DL), nerve conduction velocity (NCV), minimal F wave latency, compound motor and sensory nerve action potential (CAMP), and H reflex. As per our result, acute inflammatory demyelinating polyneuropathy (AIDP) formed the most common variant in 53.33% of cases, followed by acute motor axonal neuropathy (AMAN) in 23.35%, acute motor and sensory axonal neuropathy (AMSAN) in 3.33%, uncharacterized (16.67%) and unexcitable (3.3%). In cases with a p-value of˂.05, mean motor DL, CMAP, and NCV were significantly reduced in the tibial, peroneal, ulnar, and median nerves. The F wave minimum latency reduction was also significant, with a p-value of ˂.05. H reflex was absent in overall 89.28 % of cases. During early 0-3 days, F-wave and H reflex were the most common findings and were aberrant in 76.92% and 83.33% of cases, respectively