Written and first recorded by Ivory Joe Hunter (US #12/R&B #1 1956).
Other hit versions by Mindy Carson (US #34 1956), Bobby Vee (B-side US #81 1960), Sonny James (C&W #1 1969).
Also recorded (as “Desde que conozco”) by Freddy Fender (US #45/C&W #10 1975).
From the wiki: “‘Since I Met You Baby’ was written and first recorded by pianist Ivory Joe Hunter. The song, which Hunter recorded and charted with in 1956, has since become an American R&B standard, and saw renewed popularity in 1969 when Country music artist Sonny James released his #1 version. Hunter had already tasted major success with Pop and R&B audiences with songs such as ‘I Almost Lost My Mind‘. He moved to Atlantic Records by 1954, and around that time wrote ‘Since I Met You Baby’. Hunter’s recording topped the Billboard R&B chart for three weeks in 1956 and became his sole Billboard Hot 100 entry, peaking at #12.