The soluble transcobalamin receptor (sCD320) is present in cerebrospinal fluid and correlates with the dementia-related biomarkers phospho-tau and total-tau. Here we present data on the relation of sCD320 to Alzheimer's disease and scores of cognitive tests. Lumbar cerebrospinal fluid samples from 42 pathologically-confirmed cases of Alzheimer's disease and 25 non-demented controls were analyzed for sCD320 employing an in-house ELISA. The participants' cognitive functions were tested using the Cambridge Cognition Examination (CAMCOG) and the Mini-Mental State Examination (MMSE). There was no significant difference in the median CSF sCD320 concentration between patients and controls. The median (2.5-97.5 percentiles) sCD320 for all participants (n = 67) was 15 (3-29) pmol/L. We observed a non-linear correlation between sCD320 and cognitive scores. Spearman's correlation between sCD320 and total CAMCOG scores was 0.627 (n = 16, p = .009) for CAMCOG scores ≤27, and -0.293 (n = 39, p = .071) for CAMCOG scores ≥68. Spearman's correlation between sCD320 and both the low (≤9) and high (≥16) total MMSE scores was 0.274, -0.363 (n = 18, 44), p = .272, .016, respectively. In conclusion, sCD320 cannot be employed as a biomarker for differentiating Alzheimer dementia patients from controls. Further studies are warranted to explore the non-linear correlations between sCD320 and scores of cognitive function.