Malondialdehyde (MDA) determination is the most widely used method for monitoring lipid peroxidation. Here, we describe an easy field-amplified sample injection (FASI) CE method with UV detection for the detection of free plasma MDA. MDA was detected within 8 min by using 200 mmol/L Tris phosphate pH 5.0 as running buffer. Plasma samples treated with ACN for protein elimination were directly injected on capillary without complex cleanup and/or sample derivatization procedures. Using electrokinetic injection, the detection limit in real sample was 3 nmol/L, thus improving of about 100-fold the LOD of the previous described methods based on CE. Precision tests indicate a good repeatability of our method both for migration times (CV = 1.11%) and for areas (CV = 2.05%). Moreover, a good reproducibility of intra-and inter-assay tests was obtained (CV = 2.55% and CV = 5.14%, respectively). Suitability of the method was tested by measuring MDA levels in 44 healthy volunteers.