<jats:p>The synthesis of amorphous ultra-high molecular weight atactic polypropylene (UHMWaPP), with molecular weights (<jats:italic>M</jats:italic><jats:sub><jats:sub>w</jats:sub></jats:sub>) up to 2.0 MDa and narrow polydispersities is reported using remarkably efficient permethylindenyl-phenoxy (PHENI*) titanium complexes.</jats:p>