A splash bar for use in fill structure of an evaporative cooling tower has an extruded body with an elongated water impingement portion operable to uniformly disperse deflected water throughout the fill structure for contact with passing air. The splash bar body comprises a pair of arcuate in cross section side margins and an elongated, horizontal, flat top segment interconnecting the side margins. The centers of curvature of the side margins are coincident and lie beneath the body, while the width of the flat top segment is in the range of approximately 15% to approximately 35% of the overall width of the body. In preferred forms of the invention, the width of the flat top segment is approximately 25% of the overall width of the body. Advantageously, the body is hollow and includes a pair of spaced, flat, co-planar bottom walls integrally extending inwardly from the side margins. In alternate forms of the invention, the splash bar includes a pair of outwardly extending elongated side flanges coupled to the body and having notches adapted for clearing upright grid members, in order to substantially preclude longitudinal shifting of the bar as a result of vibration from the tower during operation.