Background: Mesobuthus eupeus is the most common type of mesobuthus belongs to the buthidae family. It is reported all over Iran and is a common cause of biting. Identifying its fractions could be helpful to draw better therapeutic approach, thus the present study was conducted in Kashan to determine different fractions of mesobuthus eupeus.

Materials and Methods: It was a descriptive study. Having prepared Tricine SDS-PAGE and heated the toyin with a buffer containing mercaptoethanol, 25 microgram, of toxin protein was injected to each plate adjusting the electrophoresis on 80V. Following the electrophoresis, 15 hours later, the produced gel was washed and fixed by methanol. Sigma ultra low MW was used to compare molecular weight of toxin protein.

Results: Mesobuthus eupeus’ toxin contains 6 protein bands. The highest one had the molecular weight of 26.96 KD whereas the lowest band had the molecular weight of 1KD. It has further proteins with lower molecular weight as compared to sigma ultra low MW.

Conclusion: Since mesobuthus eupeus could be found all over Iran, further studies are strongly recommended to determine better antivenom.