Electrical transport, both resistivity and thermopower, and heat capacity data are reported for two systems of cation vacancy-doped titanate perovskites, Nd1−xTiO3 and Sm1−xTiO3. In the former case the range of x is from 0.33 to 0.00 and for the latter from 0.17 to 0.00. Thus, the nominal carrier concentration, n, can be varied from 0 (x=0.33) to 1.0 (x=0.00) electrons per Ti atom. For the Nd series two distinct metal–insulator transitions (MIT) are seen, one obtained by electron doping the charge-transfer insulator, CTI (x=0.33), which occurs at x∼ 0.20, and the other by hole doping the Mott–Hubbard insulator, MHI (x=0.00), which is found near x∼0.10. Beginning near the CTI composition, x=0.30, evidence is found for variable range hopping from both resistivity and thermopower data. Mott metallization occurs near x=0.20 and Fermi-liquid (FL) behavior (T2 dependence of the resistivity) is seen between x=0.20 and 0.10. The coefficient of the T2 term increases with decreasing x (increasing n) and attains a large value, 3.0×10−8 Ω-cmK−2, for x∼0.12, which is more than 10 times larger than values seen in other titanate systems. Correspondingly large values for the heat capacity γ are observed. The x=0.10 sample shows a remarkable resistivity temperature dependence with a maximum at ∼175 K and minimum at ∼50 K followed by an upturn at the lowest temperatures. This is similar to behavior seen for Kondo or valence-fluctuating materials and is qualitatively consistent with existing theory, which predicts a Kondo-like transition state between the FL and MHI regimes. The x=0.05 and ∼0.00 are hole-doped antiferromagnetic semiconductors but thermopower data for the former shows a change from p- to n-type carriers just near 300 K. Sm1−xTiO3 is even more unusual as only the p-type semiconducting and the Kondo-like conducting regimes are seen. Comparisons are drawn with related Ln1−xAxTiO3 and Ln1−x TiO3 series and the role of correlation is emphasized.