diff --git a/lint.go b/lint.go
index d679f2f..67cb0a4 100644
--- a/lint.go
+++ b/lint.go
@@ -65,6 +65,7 @@
 
 	f.lintPackageComment()
 	f.lintImports()
+	f.lintBlankImports()
 	f.lintExported()
 	f.lintNames()
 	f.lintVarDecls()
@@ -141,6 +142,37 @@
 	}
 }
 
+// lintBlankImports complains if a non-main package has blank imports that are
+// not documented.
+func (f *file) lintBlankImports() {
+	// In package main and in tests, we don't complain about blank imports.
+	if f.f.Name.Name == "main" || f.isTest() {
+		return
+	}
+
+	// The first element of each contiguous group of blank imports should have
+	// an explanatory comment of some kind.
+	for i, imp := range f.f.Imports {
+		pos := f.fset.Position(imp.Pos())
+
+		if !isBlank(imp.Name) {
+			continue // Ignore non-blank imports.
+		}
+		if i > 0 {
+			prev := f.f.Imports[i-1]
+			prevPos := f.fset.Position(prev.Pos())
+			if isBlank(prev.Name) && prevPos.Line+1 == pos.Line {
+				continue // A subsequent blank in a group.
+			}
+		}
+
+		// This is the first blank import of a group.
+		if imp.Doc == nil && imp.Comment == nil {
+			f.errorf(imp, 1, "blank imports in libraries should have a comment")
+		}
+	}
+}
+
 // lintImports examines import blocks.
 func (f *file) lintImports() {
 
@@ -666,6 +698,10 @@
 	return ok && id.Name == ident
 }
 
+// isBlank returns whether id is the blank identifier "_".
+// If id == nil, the answer is false.
+func isBlank(id *ast.Ident) bool { return id != nil && id.Name == "_" }
+
 func isPkgDot(expr ast.Expr, pkg, name string) bool {
 	sel, ok := expr.(*ast.SelectorExpr)
 	return ok && isIdent(sel.X, pkg) && isIdent(sel.Sel, name)
diff --git a/testdata/blank-import-lib.go b/testdata/blank-import-lib.go
new file mode 100644
index 0000000..e9a2cd5
--- /dev/null
+++ b/testdata/blank-import-lib.go
@@ -0,0 +1,33 @@
+// Test that blank imports in library packages are flagged.
+
+// Package foo ...
+package foo
+
+// The instructions need to go before the imports below so they will not be
+// mistaken for documentation.
+
+/* MATCH /blank imports/ */ import _ "encoding/json"
+
+import (
+	"fmt"
+	/* MATCH /blank imports/ */ _ "os"
+
+	/* MATCH /blank imports/ */ _ "net/http"
+	_ "path"
+)
+
+import _ "encoding/base64" // Don't gripe about this
+
+import (
+	// Don't gripe about these next two lines.
+	_ "compress/zlib"
+	_ "syscall"
+
+	/* MATCH /blank imports/ */ _ "path/filepath"
+)
+
+import (
+	"go/ast"
+	_ "go/scanner" // Don't gripe about this or the following line.
+	_ "go/token"
+)
diff --git a/testdata/blank-import-lib_test.go b/testdata/blank-import-lib_test.go
new file mode 100644
index 0000000..0307985
--- /dev/null
+++ b/testdata/blank-import-lib_test.go
@@ -0,0 +1,20 @@
+// Test that blank imports in test packages are not flagged.
+// OK
+
+// Package foo ...
+package foo
+
+// These are essentially the same imports as in the "library" package, but
+// these should not trigger the warning because this is a test.
+
+import _ "encoding/json"
+
+import (
+	"fmt"
+	"testing"
+
+	_ "os"
+
+	_ "net/http"
+	_ "path"
+)
diff --git a/testdata/blank-import-main.go b/testdata/blank-import-main.go
new file mode 100644
index 0000000..9b72b1c
--- /dev/null
+++ b/testdata/blank-import-main.go
@@ -0,0 +1,12 @@
+// Test that blank imports in package main are not flagged.
+// OK
+
+// Binary foo ...
+package main
+
+import _ "fmt"
+
+import (
+	"os"
+	_ "path"
+)