Sixteen new limonoids, named ciparasins A-P (1-16), comprising three structural categories of trijugin-type (1-7), cipadesin-type (8-15), and prieurianin-type (16) compounds, as well as 15 known limonoid analogues (17-31), were isolated from Cipadessa cinerascens. Ciparasins E-G (5-7) were found to possess a rare γ-hydroxylbutenolide moiety at C-17. Ciparasins B (2) and P (16) showed significant anti-HIV activities, with EC50 values of 5.5 ± 0.6 (SI >7.2) and 6.1 ± 0.7 (SI >6.5) μM, respectively.