Abstract: An evaporator for refrigeration systems, comprising a set of tubes (20) arranged in series, spaced and parallel in relation to each other, carrying a refrigerant fluid and which are incorporated to and trespass a plurality of fins (10) arranged in multiple rows extending transversally to the direction of a forced airflow (F). The fins (10), which are incorporated to the first and second tubes (20) are spaced from each other by a larger distance (d), when they are operatively associated with a refrigerating environment, and by a smaller distance (d), when they are operatively associated with a freezing environment. Said distances (d) decrease at each two subsequent tubes (20), until reaching at least the third tube (20), said distance being then maintained at a minimum value for the other subsequent tubes (20).