diff --git a/insns/insn_slti.py b/insns/insn_slti.py
new file mode 100644
index 0000000..a84f502
--- /dev/null
+++ b/insns/insn_slti.py
@@ -0,0 +1,20 @@
+from insn_I import *
+
+class rvfi_insn_slti(rvfi_insn_I):
+    def __init__(self):
+        super(rvfi_insn_slti, self).__init__()
+    def ports(self):
+        return super(rvfi_insn_slti, self).ports()
+    def elaborate(self, platform):
+        m = super(rvfi_insn_slti, self).elaborate(platform)
+
+        # SLTI instruction
+        result = Signal(32)
+        m.d.comb += result.eq(Value.as_signed(self.rvfi_rs1_rdata) < Value.as_signed(self.insn_imm))
+        m.d.comb += self.spec_valid.eq(self.rvfi_valid & (~self.insn_padding) & (self.insn_funct3 == 0b010) & (self.insn_opcode == 0b0010011))
+        m.d.comb += self.spec_rs1_addr.eq(self.insn_rs1)
+        m.d.comb += self.spec_rd_addr.eq(self.insn_rd)
+        m.d.comb += self.spec_rd_wdata.eq(Mux(self.spec_rd_addr, result, 0))
+        m.d.comb += self.spec_pc_wdata.eq(self.rvfi_pc_rdata + 4)
+
+        return m