Scale instructions asked respondents to indicate on five-point scales how often they engaged in 15 intrusive acts over the past year. The scale measured the frequency and the severity of acts by a systematic process of weighting individual items before the summation of ratings. A two-part pilot study conducted with Australian college undergraduates in current heterosexual relationships found that the internal reliability of the Intrusiveness Scale was moderately high (Cronbach's alpha = .84). Similarly, the test-retest reliability for the scale was high. The correlation between the matched scores of respondents who completed the scale twice was .95. The main study involved all University of South Australia undergraduates attending a core subject in an entire division/campus. A number of standardized questionnaires were administered to the members of the sample (n=167). Findings showed that the internal reliability of the Intrusiveness Scale was stable when compared to pilot study results. Correlations were determined between Intrusiveness scores and other variables. The findings indicate that the competent psychometric properties of the Intrusiveness Scale warrant further investigation. 4 tables and 32 references