Self-guided internet-delivered cognitive behavior therapy (iCBT) has considerable public health potential for treating anxiety and depression. However, no research has examined the use of self-guided iCBT, that is, treatment without contact with a clinician, specifically for older adults. The aim of the present study was to undertake a preliminary examination of the acceptability, efficacy and health economic impact of two entirely self-guided iCBT programs for adults over 60. years of age with anxiety and depression. Two separate single-group feasibility open trials of self-guided iCBT were conducted, the Anxiety Trial (n. =. 27) and the Depression Trial (n. =. 20), using the control groups of two randomized controlled trials. The online treatment packages consisted of five online educational lessons, which were delivered over 8. weeks without clinical contact. Participants rated the interventions as acceptable with more than 90% reporting the course was worth their time and more than 70% of participants completing at least 3 of the 5 lessons within the eight weeks. Significant reductions on measures of anxiety (Generalized Anxiety Disorder 7-item; GAD-7) and depression (Patient Health Questionnaire 9-item; PHQ-9) were observed from pre-treatment to post-treatment in both the Anxiety Trial (GAD-7 Cohen's d=. 1.17; 95% CI: 0.55 to 1.75) and the Depression Trial (PHQ-9 Cohen's d=. 1.06; 95% CI: 0.33 to 1.73). The economic analyses indicated that there was statistically significant improvement in health-related quality of life compared to baseline and marginally higher costs associated with treatment for both the Anxiety Trial ($69.84; 95% CI: $4.24 to $135.45) and the Depression Trial ($54.98; 95% CI: $3.84 to $106.12). The results provide preliminary support for the potential of entirely self-guided iCBT for older adults with anxiety and depression and indicate larger scale and controlled research trials are warranted.