Basophilic stippling of red blood cells (BSC) has been noted in lead intoxication since 1899 and has been considered a classic laboratory sign of lead poisoning since that time. BSC are inclusions of aggregated ribosomes found only in the red blood cells and may be confused with siderotic (iron) granules. Heinz Bodies, or even reticulocytes. BSC are an inconstant finding in lead intoxication. In a review of peripheral blood smears from 1,000 consecutive internal medicine patients, we found BSC in 27%. These occurred in a variety of malignant, rheumatologic, hematologic, cardiovascular, and other diseases, frequently with an associated anemia. BSC may even be found in a small percentage of normal people; thus, it must be emphasized that BSC is a nonspecific finding. Furthermore, BSC has been replaced by blood lead (since the 1940s) and zinc protoporphyrin (since the 1970s) levels for biologic monitoring of lead-exposed workers.