Polarization-maintaining single-mode fibers will find application in acoustooptic sensors and fiber gyroscopes. In this study both stress-induced birefringence and elliptical core polarization-maintaining single-mode fibers were developed and evaluated. The two fiber types were compared in terms of core dimension, numerical aperture, attenuation, and beat length, a measure of the polarization maintenance. For comparative beat length values the stress-induced birefringence fibers had lower attenuation and larger core diameter than the elliptical core fibers.