The BiocIO package contains high-level abstract classes and generics used by developers to build IO funcionality within the Bioconductor suite of packages. Implements import() and export() standard generics for importing and exporting biological data formats. import() supports whole-file as well as chunk-wise iterative import. The import() interface optionally provides a standard mechanism for 'lazy' access via filter() (on row or element-like components of the file resource), select() (on column-like components of the file resource) and collect(). The import() interface optionally provides transparent access to remote (e.g. via https) as well as local access. Developers can register a file extension, e.g., .loom for dispatch from character-based URIs to specific import() / export() methods based on classes representing file types, e.g., LoomFile().