Factors which influence the MEM analysis of noise data and the correlation of noise and impedance results for coated iron electrodes were discussed. It was found that such factors as sample record length, sampling interval, stationarity of data record, trend removal and filter length of the MEM function strongly influence the MEM spectra and affect the numerical values of the retrieved system related parameters. The ways of MEM analysis optimization were suggested. Discussed was also a correlation between noise related resistances and impedance at d.c. limit.