Aims: An experiment was conducted to investigate the effect of a wide range of temperatures on the growth and physiology of Theobroma cacao, to study the differences between night and day temperatures and to determine the optimum temperature for the cocoa growth. Study Design: The experiment used five combinations of night and day temperatures (18°C and 30°C [18N30N], 18°C and 36°C; [18N 36D], 24°C and 24°C [24N24D], 24°C and 30°C [24N30D] and 24°C and 36°C [24N36D]) using complete randomized design (CRD).