Ten plates of normal fetal ultrasonography (at 16-20 weeks' gestation) showing fluid, liver, lung, bone and intestine were submitted to electro-optical transmission surface densitometry. A distinct echogenic gradient has been found and used as an 'internal standard' to evaluate intestinal echogenicity. Intestine had significantly different echogenic properties from bone, liver and fluid but similar to that of lung. Using this echogenicity scale for fetal bowel, observers were correct in 46%, overscored in 32.6% and underscored in 21.4%. These poor results may be due to the significant inconsistency in the interpretation of each plate compared to other plates (about 65%). Although the densitometry-derived grading scale seems valid at these gestational ages, interobserver variation is too large and precludes a simple ultrasonic diagnosis of the hyperechogenic fetal intestine. Densitometric evaluation may be indicated in suspected cases when fetal bowel seems to have increased echogenicity.