Alternative cleavage of the amyloid precursor protein (APP) results in generation and secretion of both soluble APP (sAPP) and β-amyloid (Aβ). Aβ is the main component of the amyloid depositions in the brains of Alzheimer's disease (AD) patients. Using Western blotting, we compared the levels of α-secretase cleaved sAPP, β-secretase cleaved sAPP and total sAPP, in cerebrospinal fluid (CSF) from 13 sporadic AD patients and 13 healthy controls. Our findings show significant amounts of β-secretase cleaved sAPP in CSF. There was no statistically significant difference in the levels of β-secretase cleaved sAPP between AD patients and controls. The levels of α-secretase cleaved sAPP and total sAPP were, however, found to be significantly lower in the AD patients than in the controls.