FeynArts 3 is a Mathematica package for generating and visualizing Feynman diagrams and amplitudes. It supports three levels of field generation: generic, classes, and particles. The package allows users to define model files for various physical models, including supersymmetric ones. It produces high-quality diagrams in PostScript or LaTeX formats for publication. FeynArts works in three steps: generating topologies, inserting fields, and applying Feynman rules to compute amplitudes. It supports counter-term diagrams and skeleton diagrams with placeholders for one-particle irreducible vertex functions. The package includes a topology editor for manual adjustments and can generate diagrams with up to three loops. It also supports mixing propagators and arbitrary adjacency of vertices. FeynArts is designed for platforms with Mathematica and Java, and has been tested on Intel-based PCs and DEC Alpha workstations. The package is open-source under the GNU GPL and is available for download from http://www.feynarts.de. It includes a comprehensive manual and is compatible with various graphics formats. FeynArts is used for field-theoretic perturbative calculations, and its output can be integrated into LaTeX documents. The package is efficient and allows for detailed customization of diagrams. It is widely used in high-energy physics for generating Feynman diagrams and amplitudes in the Standard Model and other models. The package has been developed and improved over several versions, with version 3 featuring enhanced graphics and improved user interface. It is a powerful tool for physicists working in quantum field theory and related areas.FeynArts 3 is a Mathematica package for generating and visualizing Feynman diagrams and amplitudes. It supports three levels of field generation: generic, classes, and particles. The package allows users to define model files for various physical models, including supersymmetric ones. It produces high-quality diagrams in PostScript or LaTeX formats for publication. FeynArts works in three steps: generating topologies, inserting fields, and applying Feynman rules to compute amplitudes. It supports counter-term diagrams and skeleton diagrams with placeholders for one-particle irreducible vertex functions. The package includes a topology editor for manual adjustments and can generate diagrams with up to three loops. It also supports mixing propagators and arbitrary adjacency of vertices. FeynArts is designed for platforms with Mathematica and Java, and has been tested on Intel-based PCs and DEC Alpha workstations. The package is open-source under the GNU GPL and is available for download from http://www.feynarts.de. It includes a comprehensive manual and is compatible with various graphics formats. FeynArts is used for field-theoretic perturbative calculations, and its output can be integrated into LaTeX documents. The package is efficient and allows for detailed customization of diagrams. It is widely used in high-energy physics for generating Feynman diagrams and amplitudes in the Standard Model and other models. The package has been developed and improved over several versions, with version 3 featuring enhanced graphics and improved user interface. It is a powerful tool for physicists working in quantum field theory and related areas.