Arnoldo Frigessi di Rattalma (born 1959) is an Italian statistician based in Norway, where he is a professor at the Department of Biostatistics (now called Oslo Centre for Biostatistics and Epidemiology) with the Institute of Basic Medical Research at the University of Oslo. He has also a position at the Oslo University Hospital and is affiliated with the Norwegian Computing Centre. He led the centre Statistics for Innovation, which was created in 2007 as one of 14 designated national centres for research-based innovation, funded by the Norwegian Research Council, until 2014. Frigessi and his collaborators succeeded in obtaining funding for a second centre of the same type, BiGInsight, which started in 2014 and will operate for 8 years, again under the leadership of Frigessi. Frigessi's research work has been geared towards Bayesian statistics, on both the methodogical and applied side.
Frigessi is a fellow of the Norwegian Academy of Technological Sciences. and was elected member of the Norwegian Academy of Science and Letters in 2008. He is married with Ingrid Glad and has two children, Simon and Ada.