The effective temperature for a sample of 62 solar-type stars has been determined fitting theoretical spectral profiles to observed Hα lines (6562.8 A). The stars analyzed has been observed using the 2.7 m Harlan J. Smith telescope at the McDonald Observatory of the University of Texas. The theoretical profiles are based on recent models of stellar atmospheres and quantum theory. The calculated temperatures have internal errors of ≈ 20 K with other techniques and speculate about the origin of the observed differences.