The <i>NPPB</i>:rs198389 (c.-381T > C) promoter polymorphism has been found to modulate BNP levels.<h4>Aim</h4>To investigate possible associations among the <i>NPPB</i>:rs198389 polymorphism, N-terminal pro-BNP (NT-proBNP) concentrations, and phenotypic features in Polish patients with HF.<h4>Methods</h4>The study group comprised 250 patients with HF. The gene discussed is NPPB; the disease is hydrops fetalis.