A study was conducted in Mococa, State of Sâo Paulo, Brazil, from l98l to 1989, to evaluate sunflower as a dry season optton, mahly after short-sea son soybean and maize and to study the effects of crop rotatlonal management systdns on soil chemical conditions and the yields and agronomic parameters of sunflower, soybean and maize. The treatments were: (a) Continuous sunflower grown in the wet and dry seasons (Cont. SFw/SFd); (b) Contlnuous succession soybean/dry season sunflower (Cont. S/SFd); (c) Continuous malze (Cont. M); (d) Rotation malze followed by soybean/dry season sunflower (M-S/ SFd); (e) Rotation maize followed by wet season sunflower/green manure (M-SFw/GM); (f) Rotation maize followed by wet season sunflower/dry season sunflower (M-SFw/SFd). The results show that sunflower lmproves phospho rus avatlability in the upper soll layers and lncreases soil acidification; continuous S/SFd accumulates more K at all soil depths; there is a positive lnfluence of the leguminous crop on sunflower grain and dry matter yield; for the Sâo Paulo State condltlons, maize grain yield in rotational treatments performs 30% higher than continuous maize, soybean grain and dry matter yield of the succession soybean/sunflower, even in continuous cropping, maintain the same productivity Ievels than in rotational treatments; rotational treatments has no influence ln sunflower head diameter.