Survivors of childhood lymphoma (CL) have markedly increased risk of developing heart failure. Echocardiographic studies after cardiotoxic treatment have primarily demonstrated left ventricular (LV) systolic dysfunction. In the present study, we hypothesized that longer follow-up and a more comprehensive echocardiographic examination would reveal more cardiac abnormalities. We conducted a cross-sectional study with echocardiography 20.4 ± 8.6 years after diagnosis in 125 survivors of CL, grouped according to treatment methods, and compared with matched controls. Treatment included mediastinal radiotherapy (median 40.0 Gy) in 66 and anthracyclines (median dose 160 mg/m²) in 92 survivors of CL. Abnormal LV function, left-sided valve dysfunction, or both occurred in 62 patients (50%). Diastolic dysfunction occurred in 29%. Compared with control subjects, mitral annular early diastolic velocities (e′) were reduced in patients (septal e′ 0.09 ± 0.03 vs 0.12 ± 0.03 m/s, p <0.001), and the E/e′ ratio was increased, particularly after mediastinal radiotherapy (10.6 ± 6.4 vs 5.6 ± 1.3, p <0.001). Survivors of CL had lower fractional shortening than control subjects (32 ± 6 vs 36 ± 7, p <0.001), but mean ejection fraction was equal and overt systolic dysfunction was infrequent. After mediastinal radiotherapy alone, global longitudinal myocardial strain was lower (p <0.05) compared with other treatment groups. Left-sided valvular dysfunction occurred in 55% of patients after mediastinal radiotherapy. In conclusion, survivors of CL had reduced LV diastolic function assessed by tissue Doppler imaging. This was more pronounced after mediastinal radiotherapy, which also frequently led to valvular disease. Systolic function was normal in most survivors of CL.