By using a laser induced fluorescence technique, the reactions of NH with SiH4, CH4, and C3H8 are investigated. From the first-order decay rates of NH(a1Δ, X3Σ-), the rate constants are determined to be k1 = (1.36 ± 0.02) × 10-10, k2 < 10-13, and k3 = (3.26 ± 0.17) × 10-12 (cm3 molecule-1 s-1) for the reactions NH(a) + SiH4 (1), NH(X) + SiH4 (2), and NH(a) + CH4 (3), respectively. By calibrating the LIF intensities of NH2 and H vs NH(a) using the reaction NH(a) + H2 → NH2 + H, product branching fractions for the above reactions are determined; that is, the yields of NH2 are found to be 0.39 ± 0.07, 0.86 ± 0.10, and 0.20 ± 0.05 for reactions 1, 3, and NH(a) + C3H8 (4), respectively. The yield of H atoms is concluded to be minor, and quenching of NH(a) is found to be negligibly slow in all these reactions. Time-resolved mass spectrometric measurements indicate that the main product of reaction 1 is H2.