Study Design: This will be a randomized, controlled trial with a 2 by 2 factorial design (resistance training versus no resistance training; aerobic training versus no aerobic training) in previously inactive subjects with type 1 diabetes. After screening, qualifying subjects will enter a 5-week stabilization/run in period prior to randomization. During this period their diet and insulin therapy will be assessed and optimized, and in weeks 2-5 they will also undergo three supervised sessions of low-intensity exercise per week. Those demonstrating adequate compliance during the run-in period will then be randomized in equal numbers to Aerobic Training (A) progressing to 45 min 3X/wk at 75% of maximum heart rate, Resistance Training (R) 3X/week progressing to 3 sets, 8 repetitions of 8 exercises at the maximum load that can be lifted 8 times (8RM), both Aerobic Training and Resistance Training (AR) or waiting-list control (C). The exercise intervention will take place at YMCAs in metropolitan Ottawa. Subjects cannot be blinded as to group assignment after randomization, but the main study outcomes will be measured by blinded individuals (lab technologists) using objective methods. Subjects randomized to waiting list control will begin a program of their choice (A, R or AR) after all 6-month outcome measures are collected.