Sonography can rapidly and reliably help to determine the size by the spleen. To standardise the sonographic dimensions of the healthy spleen, we effected sonographic examination of 793 female and male patients aged between 17 and 82 years with a healthy spleen. In 95% of the patients the length of the spleen was less than 11 cm, the breadth below 7 cm and the thickness less than 5 cm. The weight of the spleen as determined via the rotation ellipsoid formula was below 190 g in 95% of the patients. Whether or not a spleen larger than standard signals an acute disease can be clinically assessed only on the basis of a synopsis of all findings.