This study aimed to examine the quality of hornbill habitat in terms of tree and fruit availability in mixed deciduous forests, Kanchanaburi Province, Thailand. Salakphra Wildlife Sanctuary (SLP) has been known as a mixed deciduous forest, which has been disturbed by human activities. All canopy trees with a breast height diameter (DBH) ≥ 10 cm within the ten belt-transects of 2,000 m X 20 m (a total of 40 hectares) were monitored monthly. A total of 30 tree families including 81 species were observed on the belt-transects and the dominant species were non-hornbill fruit species. As hornbills needs emergent tree for nesting, trees with DBH size ≥ 40 cm were regarded as a potential nest tree and 37.78 % of trees were found in SLP. The abundance of preferred nest tree species (families Dipterocarpaceae, Myrtaceae and Datiscaceae) were 12.14%. The density of Ficus spp., which is regarded as the most important food source for hornbill, is 0.55 trees / ha in SLP. The Fruit Availability Index (FAI) of all fruit species during the breeding season is 23.49 % while the FAI of hornbill fruit species is 58.88 %. Furthermore, in addition to this study, a pair of Great hornbills was observed during the breeding season and the male abandoned the nest to feed the mate prior to the expected hatching period. A pair of great hornbills was observed during the breeding season in SLP and the male would only leave the nest to find and retrieve food for the female mate prior to the expected hatching period. The average estimated number of food items fed to the female mate was 220 food items during the period from March (n = 3) to 13 food items in April 2014 (n = 4). The reduction in the availability of food items may be considered as one of the factors that affect the success or failure of producing offspring.