Each specimen in the TWU Herbarium is given an accession number. Accession numbers are assigned consecutively and placed within the herbarium accession label, on the lower left corner of the specimen sheet or on the specimen envelope in case of bryophytes, etc. The accession number will be stamped on the specimen label itself, to help re-matching the label to the specimen in case the label gets separated from the specimen sheet.

Accessions are recorded in a record book with all appropriate data, including the date that the specimens were accessioned. In addition to the record book of the collection, all specimen data is available on a searchable computer database.