The molecular orientation in as-spun fibers of main-chain thermotropic liquid crystalline polymers (TLCP) has been investigated using electron diffraction at high spatial resolution. Although a large degree of macromolecular alignment with the fiber axis is expected due to the large shear stress and elongational flow associated with the spinning process, a microdefect structure with a characteristic length on the order of 100-200 nm has been revealed. The microdefect structure consists of a bimodal orientation where macromolecules are aligned along two different directions. In some cases, the macromolecular orientation is nearly orthogonal to the fiber axis. The defect structure is not observed in heat-treated fibers, and the macromolecular orientation after heat treatment is rather uniform along and across the fiber. These results are consistent with the hierarchical structure of highly oriented liquid crystalline polymers observed by Sawyer and Jaffe [J. Mater. Sci. 1986, 21, 1897-1913] and add further insight into the hierarchical defect structure of highly oriented liquid crystalline polymers.