We analyzed the absorption spectra of the skin surface taken by a mid-infrared, attenuated-total-reflection method for non-invasive measurements of blood lipid levels. The absorption spectra were acquired over several hours before and after meals and investigated the correlation with changes in blood lipid levels. The multivariate analysis results of the absorption spectra suggest the possibility of predicting concentrations of triglycerides and cholesterol in the blood. We predicted the concentration of low-density lipoprotein cholesterol from the absorption intensity at a single wavelength.