An approximate maximum likelihood method of estimation of diffusion parameters (ϑ, σ) based on discrete observations of a diffusion X along fixed time-interval [0, T ] and Euler approximation of integrals is analyzed. We assume that X satisfies a SDE of form dXt = µ(Xt, ϑ) dt + √ σb(Xt) dWt, with non-random initial condition. SDE is nonlinear in ϑ generally. Based on assumption that maximum likelihood estimatorθ T of the drift parameter based on continuous observation of a path over [0, T ] exists we prove that measurable estimator (θ n,T ,σ n,T ) of the parameters obtained from discrete observations of X along [0, T ] by maximization of the approximate log-likelihood function exists,σ n,T being consistent and asymptotically normal, andθ n,T −θ T tends to zero with rate √ δ n,T in probability when δ n,T = max 0≤i