The company's records contain administrative, financial and publicity material. The administrative series comprises the minutes of the directors from 1929 to 1955 and of the executive committee from 1949 to 1956. An engagement book records contracts between the company and its employees, 1902-1906. Henry Morgan's business correspondence covers the period 1847-1850, and includes a few personal letters to his brother James. Financial records cover both internal operations and stock transactions. The former are documented by an account book, 1845-1848; ledgers, 1870-1889; and diaries, 1884, 1936; the latter by lists of stock holders, 1954-1960; and records of transfers of Morgan's common stock, 1954-1961. Also included are files of invoices, receipts and cheques, 1846-1852. Publicity materials largely centre around anniversaries. Scrapbooks of newspaper clippings, other printed materials and photographs cover the years 1936-1945, culminating in the company's centennial, for which a typescript history was prepared.

The administrative records constitute the bulk of the collection; they include annual reports, and financial statements of John Millen & Co. and related firms, 1962-1972; quarter-monthly reports, 1956-1969; memoranda, 1961-1969; files concerning clients, products, sales, and inventory, 1960-1969; executive meetings, 1960; staff lists, 1955-1970; budgets, 1965; files on Exide & Oil Co. Sales, 1964-1968; file on Modern Sales Ltd., 1943-1970 and business correspondence, 1943-1972. Legal records consist of leases, 1963-1964; employee contract between S.B. Millen and John Millen & Son Ltd., 1968; correspondence, memoranda, and court cases, ca 1930-1936. Also included are reports and typescripts on the principles of management and sales, 1948, 1960-1969, as well as some newspaper clippings.