Abstract: An indoor enclosed fluorescent lighting fixture and luminaire implements enhanced heat dissipation. A lighting fixture includes an upper heat sink housing defining a cavity receiving at least one electrical ballast, and an upwardly open lower lens member receiving a fluorescent light source. The upper heat sink housing has a predefined heat transfer profile including generally flat elongated base wall portions for heat transfer mating engagement with a reflector positioned above the fluorescent light source and a vertically spaced apart, generally centrally located upper wall portion for heat transfer engagement with an electrical ballast.