It is known that there are difficulties in timing of ovulation induction under gonadotrophines. The reason is that investigation parameters used so far only permit indirect quantitative statements. Ultrasonics permit the direct presentation of ovaries, cystic structure-follicles, registration of their number and size as well as control of the further development. Using an typical case, possibilities with ultrasonics are demonstrated. Ovulation was induced when one follicle (0 23 mm) dominated over two others (0 17 mm), and a corpus-luteum-cyst and the pregnancy were observed. Two gestational-sacs perished during bleedings in the 9th week of pregnancy. The normal pregnancy was controlled with ultrasonics until delivery. Ultrasonic equipment was Vidoson 635 S by Siemens and Diasonograph NE 4102/B by Nuclear Enterprises.