Aim: The γ-carboxy glutamic acid (gla) containing proteins have been shown recently to have a role in calcium oxalate urolithiasis. Therefore, the effect of carboxylation on calcium oxalate monohydrate (COM) binding was studied in experimental hyperoxaluria. Methods: Urolithiasis was induced in experimental rats by oral feeding 1% ethylene glycol (EG). The microsomes were carboxylated in presence of reduced vitamin K and COM binding activity was determined. Results: Microsomal proteins adsorbed maximally with COM crystals. On carboxylation of the renal microsomal proteins, a significant increase in the COM crystal adsorption by 2.5-fold (p < 0.001) was observed in the hyperoxaluric condition. Further cyboxylated microsomes of EG-treated rats showed significant binding with calcium oxalate. Conclusion: This study presents an increased COM adsorption after the carboxylation of renal microsomes of hyperoxaluric rats.