which one is correct?

[allthewayanime]

Which form is correct?

Do you know the guy who I talked yesterday with?
Do you know the guy who I talked with yesterday?

[5jj]

Do you know the guy who I talked yesterday with?
Do you know the guy who I talked with yesterday?

The first is not natural; the second is. In BrE, many of us use 'to' rather than 'with'.

[Barb_D]

You can also omit the "who."

(If The Parser sees this, he'll also tell you that "whom" is technically the correct form there, but few people would use it.)