The 30-year-old native of Saskatoon, Saskatchewan, reached another career milestone earlier this season when he scored his 100th goal as a Blue on February 19.
Schenn also recorded his 500th career point on March 11.
His 300th assist came on a Justin Faulk goal at 7:56 of the second period, the other assist on the goal went to the recently acquired Nick Leddy. Schenn also scored a goal in that game which made him the only player on the Blues to score a goal against all 32 NHL teams.
Schenn is currently on a seven-game point streak where has put up three goals and six assists and has 21 goals, which was his sixth straight season of 20-plus goals, and 30 assists for a total of 51 points on the season.
Schenn will look to extend his point streak to eight games when the Blues host the New York Islanders tonight at 7 p.m.