Purpose: There are limited risk assessment tools validated for use with the internet child abuse material (I/CAM) offender cohort. Developed through a multi-stage process, the purpose of this paper is to present the “Estimated Risk for Internet Child Sexual Offending” (ERICSO), a new tool for I/CAM offender assessment, including demographic, collection, nature of engagement and social domains, plus a structured professional judgement section. Validation studies remain ongoing. Design/methodology/approach: This paper presents a case series analysis of six Australian men, including two Aboriginal men, convicted of I/CAM offences to pilot proposed ERICSO domains and commence validation against the short self-esteem scale, University of California Los Angles loneliness scale, internet sex screening test and the sexual violence risk-20 V2. Findings: Participants of all ages generally reported histories of mental health diagnosis and/or treatment and substance abuse. Two participants reported prior sexual offending, one for I/CAM offences. Participants expressed sexual preferences for female child victims and were convicted of possessing thousands of I/CAM files. Two participants reported accessing I/CAM for over six and 10 years, respectively, before detection by law enforcement. Practical implications: Preliminary implications indicate ERICSO higher scores are consistent with I/CAM offenders having more online sexual behaviour diversity and more areas of risk/treatment need. For example, participants with problematic self-esteem and loneliness in our data set have higher ERICSO scores. Social connectedness may be a relevant factor though definitive conclusions cannot be drawn from the small sample size. Originality/value: The ERICSO presents novel assessment of factors in considering treatment targets in addressing both illegal I/CAM and problematic legal sexual behaviours.