Background: Heterosexual anal intercourse (HAI) appears to be an increasingly frequently practiced element of the sexual repertoire, yet few studies address the attitudes, motivations and behaviors associated with HAI. Methods: Sample 1- Anal sexual behavior data from heterosexual men (N =1478). Sample 2 Attitudes about anal sex from 108 undergraduate students who completed open-ended questions were analyzed using a thematic framework. Sample 3 - A qualitative analysis of contemporary attitudes and motivations about HAI used content from news and magazine articles, and blogs. Results: Sample 1 18% of men (N=244) reported HAI within the past 30 days. Respondents with AI experience reported other anal sexual behaviors (oral/anal contact [24%], digital penetration of partner [53%]) more often than those without HAI (oral/anal contact [4%], digital penetration [10%]). Sample 2 Negative views of HAI were common, most often associated with themes of male homosexuality. Sample 3 Six predominant motivations for HAI included intimacy/trust, control/domination, novelty/variety, relationship context, pain/pleasure, and breaking taboo. Discussion: HAI is a relatively common sexual behavior, and anal sexual behaviors are not limited to penile-anal penetration. The complex interplay of motivations and stigmatizing attitudes suggest substantial difficulty in reducing risks associated with HAI. This suggests the need for more direct approaches to HAI within the context of safer sex education and STI/HIV prevention programs. New research should address the incorporation of anal-sexual behaviors into larger repertories of sexual behavior.