The present invention relates to a composition comprising high purity pyrrole derivative and method for preparation thereof. The present invention particularly relates to compositions comprising Saroglitazar magnesium having purity of 99.0% or more, and one or more of an aldehyde compound of Formula (II), diketo oxirane compound of Formula (III), hydroxy methyl compound of Formula (IV) or dimer compound of Formula (V), relative to saroglitazar magnesium, each present in an amount of about 0.15% or less, respectively, by weight, when measured by area percentage of HPLC.