Two infants who developed extreme hyperosmolality and hyperglycemia from the ingestion of inappropriately diluted powdered formula are described. Their striking similarity to some of the reported cases of "transient diabetes of the newborn" is noted, and it is suggested that there may be an etiologic relationship. Treatment consists of water replacement alone, supplemented by dialysis if necessary. Prevention requires careful instruction and possibly curtailment of the use of powdered (as opposed to liquid) formula concentrates.