SEX CRIME ON THE TRANSIT SYSTEM FALLS INTO THREE CATEGORIES (1) GENITAL EXHIBITIONISM, (2) PHYSICAL MOLESTATION, INVOLVING SOME KIND OF CONTACT BUT WITHOUT RESULTING IN SERIOUS PHYSICAL INJURY, AND (3) PHYSICAL ASSAULT RESULTING IN SEXUAL PENETRATION. ALTHOUGH NEITHER EXHIBITIONISM NOR GENITAL RUBBING (FROTTAGE) ARE CONFINED TO THE SUBWAYS, A QUALITY PECULIAR TO THE PHYSICAL SETTING OF THE SUBWAY MAKES IT A PREFERRED SITE FOR BOTH OF THESE TYPES OF SEX OFFENDERS. IN 1977, TRANSIT POLICE DEPARTMENT STATISTICS ACCOUNTED FOR ROUGHLY 75 PERCENT OF NEW YORK CITY'S TOTAL SEXUAL ABUSE AND PUBLIC LEWDNESS ARRESTS (COMPARABLE FIGURES ARE AVAILABLE FOR 1976 AND EARLY 1978). THIS STUDY REVIEWED TRANSIT POLICE RECORDS OF 2,529 SEX CRIME COMPLAINTS AND ARRESTS MADE BETWEEN JANUARY 1977 AND JUNE 1978. OVER ONE HALF WERE IN THE CATEGORY OF PUBLIC LEWDNESS CASES; SOMEWHAT LESS THAN HALF WERE DESIGNATED SEXUAL ABUSE OFFENSES; AND RELATIVELY FEW CASES (95 TOTAL) OF RAPE, ATTEMPTED RAPE AND SODOMY WERE REPORTED. OFFENDERS WERE PREDOMINANTLY BLACK AND HISPANIC; VICTIMS WHITE, YOUTHFUL, AND UNEXCEPTIONAL IN LOOKS. DATA SUGGEST THAT THE STEREOTYPE OF THE PHYSICALLY INNOCUOUS AND RELATIVELY PASSIVE EXHIBITIONIST IS INVALID. RECIDIVISTS IN THE GROUP (150) HAD A HIGHER RATE OF PRIOR ARRESTS FOR ASSAULTIVE SEX CRIMES (13 PERCENT). DATA EMERGING FROM STATEWIDE ARREST RECORDS INDICATED THAT THESE RECIDIVISTS COMMITTED A TOTAL OF 221 VIOLENT NON-SEXUAL CRIMES IN ADDITION TO THE RAPE AND SODOMY ARRESTS. WHEN BOTH SEXUALLY AND NON-SEXUALLY ASSAULTIVE CRIME ARRESTS ARE COMBINED, OVER 50 PERCENT OF THE GROUP HAD PRIOR ARRESTS FOR ASSAULTIVE CRIME. AMONG THOSE RECIDIVISTS WITH PRIOR OR SUBSEQUENT ARRESTS FOR RAPE OR SODOMY, THE ORIGINAL NON-FELONIOUS SEX CHARGE WAS JUST AS LIKELY TO HAVE BEEN PUBLIC LEWDNESS AS SEXUAL ABUSE. POSSIBLE PRE-DISPOSING FACTORS IN THE VICTIM POPULATION SUGGEST FUTURE RESEARCH. DATA TABLES AND FOOTNOTES ARE INCLUDED.