Background: Spontaneous bacterial peritonitis (SBP) is a complication to decompensated cirrhosis. Fluoroquinolones may prevent SBP. However, predictive markers for SBP are wanted. Guidelines suggest that patients with ascitic fluid protein below 15 g/l receive fluoroquinolones to prevent SBP. This study aimed to assess the clinical utility of low ascitic fluid protein in predicting SBP in patients with cirrhosis and ascites. Methods: A total of 274 patients with cirrhosis and ascites underwent paracentesis between January 2010 and June 2015. Patients were followed until two years, development of SBP, initiation of ciprofloxacin, death or liver transplantation. Data were compared between groups of patients with ‘high’ or ‘low’ ascitic protein. Results: SBP developed in 31 patients (11.3%). No difference in mean ascitic fluid protein levels were found (SBP, mean: 8.5 g/l and no SBP 8.2 g/l, p = .825). SBP developed at equal rates in patients with ‘high’ or ‘low’ ascitic protein (10.8% (≤15 g/l) and 14.0% (>15 g/l), p = .599). The same trend was observed when adjusting the threshold below 10 g/l (11.9% (≤10 g/l) and 10.2% (>10 g/l), p = .697). Conclusions: Low ascitic fluid protein does not predict SBP in patients with cirrhosis and ascites. Better markers are needed.