The World Health Organisation estimates that 466 million people worldwide have disabling hearing loss and 80% of those affected are living in low and middle income countries. Data on the impact of hearing loss or hearing aid provision in low and middle income countries is lacking. The purpose of this research project was to address the evidence gap and assess the multi-dimensional impact of hearing impairment and the provision of hearing aids on poverty, mental health, quality of life and activity participation of adults living in Guatemala. In this non-randomised controlled study 180 adult cases with an audio-metrically assessed, bilateral, disabling hearing impairment of moderate to profound severity were compared with 143 age and sex matched control participants with confirmed ‘normal’ hearing or mild, non-disabling hearing loss. All cases and controls were interviewed using a structured questionnaire. Case participants were then assessed and fitted with hearing aids. After a mean period of 7.5 months, cases and controls were re-interviewed to assess the impact of this intervention. Twenty-two in-depth interviews complemented the quantitative research. At baseline, individual earnings were 43% significantly lower among the cases than the control group. Total monthly household expenditure and per capita expenditure were significantly higher (p value = 0.001) in controls ($611, $203) as compared with cases. There was a positive association between hearing loss and the experience of depressive symptoms, but not depression. Cases were identified as having a poorer quality of life across a range of domains. At follow-up, the majority (71%) of cases reported that they used their hearing aids on a daily basis. There was no significant change in employment status for both case and control groups. Household income increased among the cases between baseline and follow-up, but not among the controls. There was no significant change to case participant’s per capita expenditure at household or 4 individual level. In contrast, for the control group there was a significant decline in the level of both household and individual per capita expenditure. There was a reduction in depression and its related symptoms and severity as well as a significant improvement in the quality of life of cases across all domains, except for social relationships. A high level of satisfaction with hearing aid use was reported globally and across a range of constituent satisfaction with amplification in daily life scores. These quantitative findings were broadly supported by the qualitative data. The research has demonstrated the positive impact that hearing aids, as part of a comprehensive fitting and aural aftercare programme may have on significantly improving quality of life and reducing symptoms of depression for people living in Guatemala. Some of the key barriers and challenges to intervention include lack of ear and hearing health awareness, stigma, financial cost and audiology clinic accessibility. The outcomes of this research have implications for ministerial advocacy, aural rehabilitation programme development and community outreach expansion.