The echocardiographic characteristics of vegetation used by precordial echocardiography (PE) have been transferred unchanged to transesophageal echocardiography (TEE), which has different image definition and structural resolution. Twelve diagnostic criteria of vegetation were tested for their accuracy in 52 patients evaluated by PE and TEE for suspected endocarditis (36 men, 16 women; mean age, 62 +/- 18 years; 42 with proven endocarditis). Results of PE and TEE were validated against gross anatomic and histologic findings. Significant differences (P < .05) included the fact that TEE disclosed more vegetations not prolapsing in the subvalvular region and in absence of valvular regurgitation. At TEE vegetations presented motion distinct from the endocardial surface, irregular conformation, and uneven margins. Only chaotic motion was significantly associated with vegetations at PE; size < 0.5 cm and increased echogenicity characterized pseudovegetations at PE. Other features such as shaggy echoes or location out of the annular zone (previously indicated as typical of vegetations) were not significantly associated with infective lesions. Discriminant analysis of TEE characteristics of vegetations disclosed that chaotic motion was the variable most significantly (P = .008) associated with vegetation. Coexistence of this sign with size < 0.5 cm and uneven margins was associated with 93.3% sensitivity and 83.7% specificity. In conclusion, the echocardiographic aspect of vegetations is rather different when examined from the precordial and the transesophageal approach. Learning about pitfalls and normal variants should improve TEE specificity in the assessment of infective lesions.