The objective of this study was to determine the influence of roasting conditions on the volatile flavor profiles and functional properties of shiitake mushrooms. Six different roasting temperatures between 80 °C and 180 °C with 20 °C increments were selected, and mushrooms were roasted for 60 min in a conventional oven. Roasting shiitake mushroom at 140 °C showed the highest levels of antioxidant activities including 2,2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhidrazyl (DPPH) radical scavenging activities, total phenols and polyphenol contents. The β-glucan ranged from 34.85% to 41.49%, and it was highest when the mushrooms were roasted at 120 °C, followed by 140 °C. Instrumental flavor analysis was conducted by Gas Chromatography using Purge and Trap, and identification of compounds were produced by NIST library. Twenty-six volatile flavor compounds were identified. The concentrations of pyrazines and furans increased with increased roasting temperatures. Shiitake mushrooms roasted at 160 °C for 60 min had the most diverse volatile flavor compound profiles. This study revealed how roasting temperatures can modulate antioxidant, functional (β-glucan) and flavor benefits.