Stability constants in 40 vol % ethanol + water mixture were evaluated for the complexes of Cd(II) and Pb(II) with the macrocyclic polyethers 15-crown-5, benzo-15-crown-5, 18-crown-6, and dicyclohexano-18-crown-6 by conductometric titrations. Complexation studies of Ag(I) with 1,4,8, 11-tetraazacyclotetradecane and 1,4,10-trioxa-7,13-diazacyclopentadecane were carried out by potentiometry to study the effect of nitrogen substituent. In addition, the stabilities of complexes of Co(II), Mn(II), and Ag(I) with oxygen-containing crown ethers were determined using the nitrate salts and were found to be lower than those obtained by using perchlorate salts in our previous study. A potentiometric study of complexes of Ag(l) was also undertaken to compare the results with those obtained by conductivity measurements, which were found to be in good agreement with each other. The complexation studies indicate 1:1 complex formation between the metal ion and macrocycle, the log K-ML(n+) values being in the range 1-9. The limiting molar conductivities of the metal ions and their crown ether complexes were also determined.