Mr. Watson — Come here — I want to see you.
Source, in full
First intelligible words spoken over the telephone (10 March 1876), as recorded in Bell's Journal entry (10 March 1876). These are often misquoted as "Mr. Watson, come here, I want you." Watson later recounted that Bell had spilled battery acid and had called for him over the phone with these words, but this may have been in a separate incident.