Thallium-201 (201Tl) scintigraphy is one of the imaging methods used in the detection of various tumors including brain metastasis. We evaluated a patient with meningeal carcinomatosis from breast cancer by using 201Tl single-photon emission computed tomography (SPECT). Meningeal spread of a tumor was noted on enhanced CT. SPECT revealed tumor localization in meningeal carcinomatosis. These results suggest that SPECT with 201Tl may be useful in detecting meningeal carcinomatosis from breast cancer.