Purpose To determine T2 relaxation times of lipid and macromolecules (Lip/MMs) observed by 1H magnetic resonance spectroscopy (1H MRS) of metastases (MET) and glioblastomas (GBM), so that they may be better characterized. Materials and Methods 1H spectra were acquired at multiple echo times from brain lesions using point-resolved spectroscopy sequence (PRESS) at TE = 30 msec either with metabolite-nulling (six GBM and 11 MET), or without metabolite-nulling (four MET and one mucocele). All lesions were previously untreated and had subsequent histopathological classification. Results The T2 of the 1.3-ppm Lip/MM peak was concentration-dependent, but at high concentrations it was significantly different ( P = 0.015) between GBM (42 ± 6 msec) and MET (63 ± 18 msec). The broad 2.05-ppm and 0.09-ppm Lip/MM peaks had similar T2s in MET and GBM. The T2 of the narrow 2.05-ppm Lip/MM peak sometimes observed had a T2 of 100 ± 17 msec in MET and 75 msec in the mucocele. Conclusion We observed significantly higher T2 of the 1.3-ppm Lip/MM peak in MET compared with GBM at high 1.3-ppm proton concentrations, in agreement with a higher 1.3/0.9-ppm peak ratio found in MET. The relatively long T2 of the 2.05-ppm Lip/MM peak sometimes observed in MET may cause it to be confused with N-acetyl aspartate (NAA). J. Magn. Reson. Imaging 2007. © 2007 Wiley-Liss, Inc.