Using panel data on 500 foreign manufacturing affiliates in Japan over the period 1991-2000, fixed effect estimates indicate that partnership with a local firm increases the growthpotential of foreign firms but is less beneficial for larger and older foreign affiliates. Also, itis found that size and age have significant effects on foreign affiliate growth asdemonstrated in previous studies on domestic firms.Hence, the size, age, and ownershipstructure of foreign affiliates appear to be important considerations in determining long-term growth potential from a policy perspective.