The pure rotational transitions in the 220–460 GHz spectral range of TiO (X3Δr) and TiN(X2Σ+) have been observed using a source-modulated submillimeter-wave spectrometer. In addition, the two lowest rotational transitions of TiO at 63 and 94 GHz have been observed using molecular beam pump/probe microwave optical double resonance (PPMODR) technique. An improved set of spectroscopic parameters for TiO(X3Δ) was generated by combining the new PPMODR and submillimeter-wave absorption measurements. Similarly, an improved set of spectroscopic parameters for TiN(X2Σ+) was generated by combining the new submillimeter-wave absorption measurements with the previously recorded PPMODR measurements (D. A. Fletcher, C. T. Scurlock, K. Y. Jung, and T. C. Steimle, 1993,J. Chem. Phys.99, 4288). The determined Λ-type doubling parameter for the TiO(X3Δ) is compared with the theoretical model.