This study investigates the determination of the mechanical performance of polyamid 66 and the influence of moisture and short glass fiber content (15 wt.-% and 30 wt.-%) at six different conditioning times (1, 2, 4, 8, 16, 32 minutes) in 105 degrees C water vapor. It was determined that as the glass fiber content increases, moisture absorption decreases. While the moisture absorption increases, tensile strength decreases and the percental elongation and toughness increases. It can also be derived that continuation of moisture absorption after 16 minutes is not effective and beneficial. The moisture absorption values observed in this study are equivalent to the amount of moisture that can be absorbed at 50 % relative humidity and 23 degrees C room temperature in the air for four months.