The contractility of the oviduct of Chrysemys picta (the fresh-water turtle) was studied in vitro. Significant regional differences in contractile activity were observed. Contractions increased in amplitude and duration and decreased in frequency from the proximal to the distal end of the oviduct. Injections of oestradiol-17beta in vivo increased the amplitude of contractions and decreased the duration of the rest period in segments taken from the diatal end of the oviduct. In contrast, progesterone injections significantly reduced the duration of both contractile and resting periods.