Previous experimental studies reported the temperature induced degradation of mechanical properties of different grades of structural steel. Connections play a crucial role in transferring forces between structural members. The performance of bolted connections, under fire conditions, depends on the strength of bolts. This paper presents results from experimental studies on mechanical properties of Grade 10.9 bolts at elevated temperatures. The high-temperature mechanical properties including stress-strain response, yield and ultimate strengths are evaluated in the range 20-800°C. Data from the tests indicate that bolts experience rapid reduction in strength at temperatures beyond 400 °C and reaches to 5% of ambient ultimate strength when heated to 800 °C. The use of obtained reduction factor for strength of Grade 10.9 bolts can lead to better assessment of residual capacity and performance of fire induced bolted connections. Test data also indicate that strength of Grade 10.9 steel bolts degrade faster than that of conventional steel.