Cobalt(II) carbonate, CoCO3.4H2O and lead(II) carbonate, PbCO3.2H2O were synthesis by a new simple method during the reaction of aqueous solutions of CoX2 (X=Cl-, NO3- and CH3COO-) and PbX2 (X=NO3- or CH3COO-), respectively, with urea at approximately 85 degrees C for 2 h. The infrared spectra of the reaction products clearly indicates the absence of the bands due to coordinated urea, but show the characteristic bands of ionic carbonate. A general mechanisms describing the formation of cobalt and lead carbonates are suggested.