Strain and dimensional confinement can be used to tune magnetic and ferroelectric properties or enhance device performance. In epitaxial films, the different lattice spacing of an underlying substrate can be used to impose a biaxial strain. We have studied the effect of the substrate-induced biaxial strain on the electrical conductivity and magnetic properties of manganite compounds. Epitaxial (001) La 0.7Sr 0.3MnO 3 thin films have been grown by reactive molecular-beam epitaxy (MBE) on single crystalline substrates, varying the substrate-induced biaxial strain from -2.3% to +3.2%. The strain caused the Curie temperature to decrease by up to 100 K in very good agreement with the predictions of Millis et al. [A. J. Millis, T. Darling, and A. Migliori, J. Appl. Phys. 83, 1588 (1998)]. The effect of dimensional confinement on manganites was also investigated in thin films by synthesizing a superlattice of two formula-unit-thick layers of CaMnO 3 separated by CaO double layers, i.e., the n=2 Ruddlesden-Popper phase Ca 3Mn 2O 7. Magnetization measurements on 30 nm thick (001)-oriented Ca 3Mn 2O 7 thin films grown on (110) YAlO 3 substrates by MBE reveal a Neél transition temperature of T N=115 K, similar to bulk Ca 3Mn 2O 7, but 10 K lower than thick CaMnO 3 films grown on this same substrate.