The basic mechanical properties of a series of injection moldings of the thermotropic liquid crystalline polymer Vectra have been investigated to determine the effect of fillers on the short- and long-term mechanical properties of these materials. Mineral-filler addition results in a slight decrease in strength and an increase in stiffness in the flow direction, but has relatively little effect on the anisotropy. Glass fiber addition, on the other hand, may substantially lower the anisotropy depending on the degree of fiber orientation transverse to the flow direction. The glass fiber-filled grade investigated also showed improved creep properties at high temperature compared with both the unfilled and mineral-filled grades. © 1993 John Wiley & Sons, Inc.