In this paper, symmetrical CMOS OTA degradation is investigated with using statistical methods. OTA’ s are degraded using 4155 parameter analyzer and output current change is observed. An appopriate fitting curve is realised with MATLAB programme by taking into consedaration the error. Lifetime of the OTA’s are determined with the %10 lifetime criteria. And probability density function is observed and lifetime is calculated statistically. Also, failure rate, reliability function and the cumulative distribution functions are observed.