In this study, Monte Carlo statistical mechanical simulations for vinblastine and vincristine werecarried out in standard manner using the Metropolis sampling technique in canonical (T, V, N)ensemble., Geometrical optimizations of vinblastine and vincristine were carried out with the HFmethod coupled to 6-31G(d) basis sets for all atoms. Simulation was done by four force fields ofMM+, BIO+, AMBER and OPLS. Some important energy parameters such as Potential Energy andTotal Energy in ten different simulating temperatures (300, 302, 304, 306, 308, 310, 312, 314, 316and 318 Kelvin) were used for computation. Manuscript profile