Raised bogs started to form in Ireland at least 7000 years ago when peat started to accumulate in water-filled depressions left after the last glacial period. Due to centuries of damaging human activities, only 1% of the living, growing active raised bog habitat remains and this is rapidly being lost. Raised bogs are important reservoirs of biodiversity, hosting many uniquely adapted plant and animal species and are of high conservation concern internationally. The aims of this study were to objectively assess the potential of macro-moths as active raised bog biodiversity indicators, to collate baseline information on the distribution of this fauna on threatened midland raised bog habitat and to identify species with restricted distributions which may be of conservation concern. Macro-moths were sampled using light-traps on twelve midland raised bogs from early July to the end of October in 2011. Six high conservation value bogs designated as Special Areas of Conservations (SACs) and six undesignated and degraded bogs were surveyed. A total of 1,816 adult individuals of 93 moth species were recorded, representing 16% of the Irish moth fauna. Four species new to County Offaly were recorded. Only two potential indicator species of active raised bog were found, with only one species (Acronicta menyanthidis (Esper, 1789)) significantly correlated with the wettest areas of active raised bog (P = 0.01). Raised bog associated nocturnal macro-moth assemblages showed a significantly nested structure (P < 0.01), common in fragmented habitats, whereby species-poor sites form a nested subset of species-rich sites. The difference between designated and undesignated raised bog associated moth assemblages was significant (A = 0.044; P = 0.038), but within group homogeneity was low. As designated and undesignated bogs contain assemblages which are broadly similar, the findings of this study would suggest that even degraded undesignated raised bog remnants, may be of significant conservation value for macro-moth species.