diff --git a/src/DecFP.jl b/src/DecFP.jl
index 41ec941..4698377 100644
--- a/src/DecFP.jl
+++ b/src/DecFP.jl
@@ -807,6 +807,8 @@ promote_rule(::Type{Irrational{s}}, T::Type{Complex{F}}) where {s,F<:DecimalFloa
 Base.widen(::Type{Dec32}) = Dec64
 Base.widen(::Type{Dec64}) = Dec128
 
+Printf.tofloat(x::DecimalFloatingPoint) = BigFloat(x)
+
 macro d_str(s, flags...) parse(Dec64, s) end
 macro d32_str(s, flags...) parse(Dec32, s) end
 macro d64_str(s, flags...) parse(Dec64, s) end
diff --git a/test/runtests.jl b/test/runtests.jl
index bab4a02..e81e1b2 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -184,6 +184,9 @@ for T in (Dec32, Dec64, Dec128)
 
     @test @sprintf("%.2f %.4f", T("12.34567"), 9.87) == "12.35 9.8700"
 
+    # issue #178
+    @test @sprintf("%.36f", T("0.1")) == "0.100000000000000000000000000000000000"
+
     x,y,z = 1.5, -3.25, 0.0625 # exactly represented in binary
     xd = T(x); yd = T(y); zd = T(z)