Besides mechanized transportation horses have still global importance not only for the communication but it is thought as symbol of superiority in many countries of the world. Horses are confronted with colic once in their life span that some times results in uncompareable loss to the owner. Only a timely and accurate diagnosis is the beacon of hope to save the life. To study the effects of colic on PCV and Blood Electrolytes, twenty horses suffering from colic were taken into investigation to asses the site and type of colic, while ten normal horses were kept as control. Diseased horses were divided into three groups A, B & C mild, moderate and severe respectively. Physical signs of group A were of mild nature comprising swishing of the tail, looking at the flank and lying down for the short periods, while group B showed moderate pain like lying down but not violently and increased bouts of pain. Animals in group C exhibited signs of severe pain by showing severe depression, restlessness, patchy sweating, struggling violently and kicking at the belly due to sharp continuous pain. The heart rate, respiration and rectal temperature in all groups was increased. Rectal palpation was performed in all groups to determine the site of the disease. Changes found in blood electrolytes like Na+, K+, C1- and HCO3 were measured by flame photometry. Group A, B and C showed decrease in Na+, and HCO3 concentration in serum while concentration of K and C1 in serum were normal in all groups. PCV was measured by Wintrobe micro-haematocrit method in all groups. Group A and C showed normal PCV but it was lower in group B. These all observations showed that the animals of group A were suffering from impaction of ileacaecal valve. Pain was not so severe nature that may cause death in colic cases while the animals in group B were showing signs of spasmodic colic. The abnormalities were not so severe to threat the life of the animal but were elevated than the normal. Group C was considerably serious that might lead to death if unattended because the variations and findings were similar with obstruction of small intestine. The serum electrolytes in this group were increased than the other two groups alongwith the elevated respiration, heart rate and rectal temperature that were helping in assessing the condition of the animal. PCV was the reliable tool to know the degree of dehydration in the severe cases. Rectal palpation helped in differentiating the various segments of the intestines involved and the severity of the disease in the diseased animals.