The purpose of this study was to examine the role initial attack and expertise play in the identification of instrumental tones. A stimulus CD was made of 32 excerpts of instrumental tones. Sixteen possible combinations of the variables of initial attack (present or absent), expertise (beginner versus professional), and timbre (flute, clarinet, alto sax, trumpet) were recorded twice, once on B-flat4 and once on F4. After listening to the excerpts, music major (n = 100) and non-major participants (n = 112) identified the instrument that was performed in the excerpt and the expertise level of the performer of the excerpt. A list of possible instruments was provided that included the four stimulus instruments as well as four distractor instruments. Data analysis revealed initial attack presence had a significant main effect on instrument identification, especially for music majors' identification of performer expertise. Results suggest presence and possibly quality of the initial attack affect timbre identification and tone quality assessment.