The objective of this research was to determine the factors associated with disclosure of three treatable sexually transmitted diseases (STDs). Data were obtained from two intervention trials to determine the ideal means of partner referral. Men diagnosed with urethritis and women diagnosed with trichomoniasis at public clinics in New Orleans, Louisiana were randomly assigned to partner referral (PR), booklet-enhanced partner referral (BEPR), or patient-delivered partner treatment (PDPT). Participants were asked about sex partners at baseline, then whether they disclosed to them at follow-up. The male trial was conducted from December 2001 to March 2004 and the female trial from December 2001 to August 2004. Data on men and women were analyzed separately. Nine hundred seventy-seven men and 463 women-reporting information on 1991 and 521 sex partners-were respectively enrolled in each trial. Disclosure occurred to 57.8% and 87.3% of their partners, respectively. Most men (68.3%) reported having two or more partners and disclosure was more likely to occur in: those who reported only one sex partner (adjusted odds ratio [aOR] 95% confidence interval [CI]: 1.54 [1.10, 2.16]); those in steady relationships (OR [95% CI]: 1.37 [1.08,1.74]); and those assigned PDPT [OR [95% CI]: 2.71 [1.93,3.82]). Most women reported having only one partner (86.8%) and disclosure was more likely to occur in steady relationships (OR [95% CI]: 2.65 [1.24,5.66]), and when sex was reinitiated with partners during the follow-up period (OR [95% CI]: 3.30 [1.54,7.09]). The provision of PDPT was associated with increased STD disclosure among men but not among women. Both men and women were less likely to disclose to casual partners. Women had high rates of disclosure irrespective of intervention arm.