abstract: We say that a polynomial $P(x{1},...,x{n})$ (with coefficients in $\mathbb{Z}$) is partition regular on $\mathbb{N}=\{1,2,...\}$ if whenever the natural numbers are finitely colored there is a monochromatic solution to the equation $P(x{1},...,x{n})=0$. While the linear case has been settled by Richard Rado almost a century ago, not very much is known for nonlinear polynomials. Using a technique that mixes ultrafilters and nonstandard analysis, we prove that the partition regularity can be ensured for the elements of two "natural" classes of nonlinear polynomials.