Our major aim of this study was to to evaluate diurnal effects on two key MR metrics; total brain volume and neurometabolite profiles. Repeated 3D-MPRAGE and 1D-MRS were undertaken over a 10-hour period on 10 healthy subjects (aged 36.1±7.7 years). Volumetric analysis, using vendor segmentation software, did not reveal any statistically significant effect of time of day or sex on total brain volume. Spectral data processing and analysis using LCModel showed a mild increase in glycerophosphocholine and total choline levels between 7am and 12pm. Our study suggested a lack of significant diurnal effect on these parameters.