(1) Background: Aboriginal women have a higher mortality from cervical cancer, yet cervical screening rates are lower than for other Australian women. (2) Methods: A randomised controlled trial of reminder letter vs. phone call/SMS for routine cervical screening testing in an Aboriginal Community Controlled Health Organisation in NSW. (3) Results: 256 women aged between 25 and 74 who were due for cervical screening were randomised to receive a reminder letter (and up to two further letters for non-responders) or a phone call (followed by up to two SMS) to attend the screening. A total of 15 women (12.5%) attended for cervical screening test within 3 months following a letter, and 24 women (17.6%) after a phone call/SMS reminder; this difference was not significant (p= 0.252). Time spent on sending letters vs. phone calls/SMS was similar; the cost was lowest for SMS. (4) Conclusion: Response to reminders was lower than expected. While there was no significant difference in effectiveness in letter vs. phone call/SMS for cervical screening recalls, reminder systems, including opportunistic reminders, can play a role in encouraging women to participate in screening programs in conjunction with national screening registers. The choice of reminder type should be left to service and consumer preference.