Abstract. This paper describes a method for determination of mechanical properties (elastic parameters) of weft knitted GF/PP textile composite using the results of modal tests. The method uses the classical approach of minimization of the discrepancy between physically measured and numerically calculated natural frequencies. The method is improved by taking into account the errors caused by spreading the geometrical and physical parameters of sam-ple specimens. The Monte Carlo simulation is used for obtaining correlations between fre-quency deviations. These correlation coefficients and deviations of physical frequency measurements are used for confidence interval calculations for the identified parameters. The method allows making the optimal choice of frequency sets and weighting coefficients for identification of each identifiable parameter. The error analysis proved that the Poisson’s ra-tio can also be determined from bending oscillation modes of plate type specimens. The method was used to determine the influence of climate cycle temperature effects on composite materials, including cryogenic temperatures, elevated temperatures and thermal cycling be-tween these extremes.