AbstractPepper (Piper nigrumL.) is traditionally harvested immature in Sri Lanka. The effect of maturity on starch content, volatile oil content and composition and piperine content is reported here. Although maturity affected the essential oil and piperine content, the oil composition remained largely unaffected. Most oil synthesis appeared to have taken place by 23 weeks. The piperine content reached a maximum (14.2%) at 19 weeks and then declined, although the total content per berry continued to increase until full maturity. As expected, starch synthesis dominated the second half of development, attaining a value of over 50% dry weight on ripening. Immature harvest alone cannot explain the relatively high levels of piperine and volatile oil in Sri Lanka pepper.