Let V be a complex non-singular projective 3-fold of general type with χ(ω V ) ≥ 0 (resp. > 0). We prove that the m-canonical map Φ |mK V | is birational onto its image for all m ≥ 14 (resp. ≥ 8). Known examples show that the lower bound r 3 = 14 (resp. = 8) is optimal.