PIP: The study purpose was to determine the relationship(s) of the source of contraceptive knowledge to contraceptive knowledge accuracy and contraceptive behavior of college freshmen. Sources of contraceptive knowledge were divided into 2 categories for the purposes of this study: structures/organized sources -- schools, church, college, planned parenthood, and health services; and unstructured/unorganized sources -- home, peers, sexual partner, and mass media. The sample consisted of 340 1st or 2nd semester college freshmen (58.5% males and 41.5% females) entering a required health education course at a midwestern college. Participants were volunteers. Subjects were given a 67-item contraceptive-knowledge test previously utilized by Reichelt and Wereley (1976). The survey instrument was modified to include a section pertaining to sources of contraceptive knowledge. The sources of contraceptive knowledge the students identified revealed that peers and the mass media were the major contributors. The unorganized/unstructured sources of information contributed more to the knowledge level than did the organized/structured sources. School was the largest source of information in the organized/structured category; 34 subjects stated 50% or more of their knowledge came from school, and a total of 164 subjects identified school as a source. All other organized/structured sources were identified as having contributed little to contraceptive knowledge. To determine if the source of contraceptive knowledge affected the accuracy of this knowledge, subjects were divided into organized/structured sources and unorganized/unstructured sources of knowledge acquisition. Overall, the contraceptive knowledge accuracy of the subjects was poor. Contraceptive knowledge accuracy exceeded 70% for only the "other" (less effective) category; knowledge accuracy from all other categories was less than 70% for both organized and unorganized sources. For each of the 6 categories of contraceptive method (oral contraceptive, IUD, condom, diaphragm, spermicides, and the less effective methods), the subjects from organized/structured sources scored higher than the unorganized/unstructured sources. Knowledge accuracy concerning the IUD was exceedingly poor for both organized (39%) and unorganized (29%) sources. The largest difference between knowledge sources and accuracy was in the "other" category. Subjects from the organized/structured source had a 72% accuracy; those from the unstructured/unorganized source had only a 58% accuracy. Of the 89 subjects from the organized/structured source and the 55 from the unorganized/unstructured source who were sexually active at the time of the study, the organized/structured knowledge source subjects used oral contraceptives more and used "other" methods less than did the unorganized/unstructured group (46% and 34% and 19% versus 25% respectively.