Serum chromogranin A is the most useful general and prognostic tumour marker available for neuroendocrine tumour (NET) patients. The role of other tumour markers is less clear. In order to determine the diagnostic and prognostic value of serum alpha-fetoprotein (AFP) and human chorionic gonadotrophin-beta (hCGbeta) in NETs, a database containing biochemical, histological, and survival data on 360 NET patients was constructed. This data was statistically assessed, using Statistical Package for the Social Sciences, to determine the utility of commonly measured tumour markers with particular emphasis on AFP and hCGbeta. Alpha-fetoprotein and hCGbeta were raised in 9.5 and 12.3% of patients respectively and jointly raised in 9.1% of patients in whom it was measured. Alpha-fetoprotein levels associated strongly and positively with tumour grade, serum CgA and hCGbeta levels, and worse survival. Human chorionic gonadotrophin-beta levels also associated strongly and positively with serum CgA and AFP levels, and worsening survival. Alpha-fetoprotein and hCGbeta are elevated in high-grade NETs, with a rapidly progressive course and poorer survival. They also correlate with chromogranin-A, which is known to be a marker of tumour burden and to have prognostic value. Thus AFP and hCGbeta are clinically important in NETs and when elevated are poor prognostic markers.