The article considers the problem of identifying a mathematical model in the form of a system of ordinary differential equations. The identified system can have constant and periodic coefficients. The source of information for solving the problem is time series of observed variables. The article studies the effect of uniformly distributed noise on the identification result. To solve the problem, the algorithm proposed by the author in previous works was used. It is shown that the method has different sensitivity to noise depending on which of the observed variables is contaminated with noise. The implementation of the method is illustrated by numerical examples of identifying nonlinear differential equations with polynomial right-hand sides.