Data analysis commonly involves visualization of data. This includes both plotting the data themselves and plotting properties of the dataset like frequencies of certain numbers. R is a very well-established platform for scientists in general and computational biologists in particular. Besides from being a programming environment for statistical computing, R is also a data visualization tool. Several topic specific packages are available to analyze and visualize experimental data, e.g. for evolutionary biology, the evaluation of biochemical assays, nucleotide and amino acid sequence analysis, microarray data interpretation, and more. This chapter provides a basic introduction, exemplifies statistical data analysis, demonstrates installation of additional packages, and shows how to retrieve data from a MariaDB or MySQL database. All files from this chapter are available from the book’s GitHub repository at CompBiol3/17_RStudio .