Flow properties of aluminum and aluminum-boron carbide (Al-B₄C) composites, containing 5, 10 and 15 wt% B₄C, were investigated by compression tests at strain rates of 10^–4, 10^–3 and 10^–2 s^–1 over the temperature range 25 to 500°C. The nature of stress–strain curves as a function of reinforcement, temperature and strain rate revealed that (1) flow stress initially increases as the reinforcement increases, but it decreases for Al-15% B₄C composite, (2) flow stress increases with the increase in strain rate, with the strain rate sensitivity index varying from 0.01 for aluminum at 200°C to 0.30 for Al-5% B₄C composite. The activation energy for deformation is found to vary from 124 to 187 kJ/mol for Al-15% B₄C and Al-5% B₄C composites, respectively.