One lawyer said he has to be compensated for his 'loss of innocence.'
The Bar confirmed it sent the email out and publicly apologized on Twitter saying it is 'horrified'.
Its tweet read: 'Apologies to all who received an inappropriate email from the Utah State Bar. We are aware of the situation and are investigating the matter.'
Executive director John Baldwin said: 'We are horrified. We are investigating to discover how this occurred. Our goal is to find out what happened and insure it never happens again.'
Matt Page, communications director, said the email was created 'in-house', and that he himself made the image advertising the spring event, which didn't include a picture of a topless woman.
The email contained the subject line '2018 Spring Convention Walk-Ins Welcome! Learn How!' along with an image promoting the March 8-10 event.
Many people on Twitter found the email highly amusing with one person writing: 'Hey Utah Lawyers: DO NOT OPEN THE LATEST STATE BAR EMAIL AT WORK! VERY NSFW AND I CANT STOP LAUGHING.'
Twitter user Zach Bloxham joked: 'The Utah Bar just sent me an email that included a picture of a topless woman. I will be deducting $100 off of my next bar dues to compensate for my loss of innocence.'
Chase Thomas said: 'Opened up that email in the middle of the House gallery and freaked out! My intern sitting next to me was laughing so hard.'