More effective clinical use of the Southern California Postrotary Nystagmus Test (SCPNT) may result if factors affecting test reliability were known. An experiment, a pilot study involving primary grade students, was designed to assess whether time of day or sex affected the test. The SCPNT was administered at a 2-week interval to 12 boys and 12 girls and subject responses were noted and compiled. Pearson Correlation Coefficients revealed high reliability for all conditions. No significant differences existed for sex or time of retest. Responses to the SCPNT revealed that it was typical for a subject to demonstrate pleasure but not typical to show alarm, threat, or loss of body balance while rotating.