Enzymatic method for formaldehyde assay, based on formaldehyde dehydrogenase from the recombinant strain of the yeast Hansenula polymorpha, was developed. Linear detection range for the proposed method was estimated to be from 0.01 to 0.05 mM, and sensitivity of the assay (or detection limit) was determined as 0.007 mM. In comparison with the known methods, the described procedure is rather simple: the method does not require transformation of formaldehyde into chemical adduct for the extraction of the target analyte from the tested sample. As compared to chemical methods, the analysis time is shorter and some dangerous operations (e.g. heating in strong acid) are not required. The developed method is approved on the real samples which contained formaldehyde, and data are well correlated with the results of the known chemical methods.