diff --git a/promql/functions.go b/promql/functions.go
index 71dffd3b4..60548f312 100644
--- a/promql/functions.go
+++ b/promql/functions.go
@@ -327,48 +327,6 @@ func funcClampMin(ev *evaluator, args Expressions) Value {
 	return vec
 }
 
-// === drop_common_labels(node ValueTypeVector) Vector ===
-func funcDropCommonLabels(ev *evaluator, args Expressions) Value {
-	vec := ev.evalVector(args[0])
-	if len(vec) < 1 {
-		return Vector{}
-	}
-	common := map[string]string{}
-
-	for _, l := range vec[0].Metric {
-		// TODO(julius): Should we also drop common metric names?
-		if l.Name == labels.MetricName {
-			continue
-		}
-		common[l.Name] = l.Value
-	}
-
-	for _, el := range vec[1:] {
-		for k, v := range common {
-			for _, l := range el.Metric {
-				if l.Name == k && l.Value != v {
-					// Deletion of map entries while iterating over them is safe.
-					// From http://golang.org/ref/spec#For_statements:
-					// "If map entries that have not yet been reached are deleted during
-					// iteration, the corresponding iteration values will not be produced."
-					delete(common, k)
-				}
-			}
-		}
-	}
-
-	cnames := []string{}
-	for n := range common {
-		cnames = append(cnames, n)
-	}
-
-	for i := range vec {
-		el := &vec[i]
-		el.Metric = labels.NewBuilder(el.Metric).Del(cnames...).Labels()
-	}
-	return vec
-}
-
 // === round(Vector ValueTypeVector, toNearest=1 Scalar) Vector ===
 func funcRound(ev *evaluator, args Expressions) Value {
 	// round returns a number rounded to toNearest.
@@ -405,14 +363,6 @@ func funcScalar(ev *evaluator, args Expressions) Value {
 	}
 }
 
-// === count_scalar(Vector ValueTypeVector) float64 ===
-func funcCountScalar(ev *evaluator, args Expressions) Value {
-	return Scalar{
-		V: float64(len(ev.evalVector(args[0]))),
-		T: ev.Timestamp,
-	}
-}
-
 func aggrOverTime(ev *evaluator, args Expressions, aggrFn func([]Point) float64) Value {
 	mat := ev.evalMatrix(args[0])
 	resultVector := Vector{}
@@ -1052,12 +1002,6 @@ var functions = map[string]*Function{
 		ReturnType: ValueTypeVector,
 		Call:       funcCountOverTime,
 	},
-	"count_scalar": {
-		Name:       "count_scalar",
-		ArgTypes:   []ValueType{ValueTypeVector},
-		ReturnType: ValueTypeScalar,
-		Call:       funcCountScalar,
-	},
 	"days_in_month": {
 		Name:       "days_in_month",
 		ArgTypes:   []ValueType{ValueTypeVector},
@@ -1091,12 +1035,6 @@ var functions = map[string]*Function{
 		ReturnType: ValueTypeVector,
 		Call:       funcDeriv,
 	},
-	"drop_common_labels": {
-		Name:       "drop_common_labels",
-		ArgTypes:   []ValueType{ValueTypeVector},
-		ReturnType: ValueTypeVector,
-		Call:       funcDropCommonLabels,
-	},
 	"exp": {
 		Name:       "exp",
 		ArgTypes:   []ValueType{ValueTypeVector},
diff --git a/promql/testdata/legacy.test b/promql/testdata/legacy.test
index 1556485f8..607c2819c 100644
--- a/promql/testdata/legacy.test
+++ b/promql/testdata/legacy.test
@@ -125,14 +125,6 @@ eval instant at 50m rate(testcounter_zero_cutoff[20m])
 	{start="5m"} 0.6
 
 
-# count_scalar for a non-empty vector should return scalar element count.
-eval instant at 50m count_scalar(http_requests)
-	8
-
-# count_scalar for an empty vector should return scalar 0.
-eval instant at 50m count_scalar(nonexistent)
-	0
-
 eval instant at 50m http_requests{group!="canary"}
 	http_requests{group="production", instance="1", job="app-server"} 600
 	http_requests{group="production", instance="0", job="app-server"} 500
@@ -149,9 +141,6 @@ eval instant at 50m http_requests{job!~"api-.+",group!="canary"}
 	http_requests{group="production", instance="1", job="app-server"} 600
 	http_requests{group="production", instance="0", job="app-server"} 500
 
-eval instant at 50m count_scalar(http_requests{job=~"server"})
-	0
-
 eval instant at 50m http_requests{group="production",job=~"api-.+"}
 	http_requests{group="production", instance="0", job="api-server"} 100
 	http_requests{group="production", instance="1", job="api-server"} 200
@@ -244,10 +233,6 @@ eval instant at 50m sum_over_time(http_requests{group="production",job="api-serv
 eval instant at 50m time()
 	3000
 
-eval instant at 50m drop_common_labels(http_requests{group="production",job="api-server"})
-	http_requests{instance="0"} 100
-	http_requests{instance="1"} 200
-
 eval instant at 50m {__name__=~".+"}
 	http_requests{group="canary", instance="0", job="api-server"} 300
 	http_requests{group="canary", instance="0", job="app-server"} 700
@@ -283,11 +268,9 @@ eval instant at 50m absent(nonexistent)
 eval instant at 50m absent(nonexistent{job="testjob", instance="testinstance", method=~".x"})
 	{instance="testinstance", job="testjob"} 1
 
-eval instant at 50m count_scalar(absent(http_requests))
-	0
+eval instant at 50m absent(http_requests)
 
-eval instant at 50m count_scalar(absent(sum(http_requests)))
-	0
+eval instant at 50m absent(sum(http_requests))
 
 eval instant at 50m absent(sum(nonexistent{job="testjob", instance="testinstance"}))
 	{} 1
@@ -370,19 +353,6 @@ eval instant at 50m log10(vector_matching_a - 20)
 
 
 # Matrix tests.
-
-clear
-load 1h
-	testmetric{testlabel="1"} 1 1
-	testmetric{testlabel="2"} _ 2
-
-eval instant at 0h drop_common_labels(testmetric)
-	testmetric 1
-
-eval instant at 1h drop_common_labels(testmetric)
-	testmetric{testlabel="1"} 1
-	testmetric{testlabel="2"} 2
-
 clear
 load 1h
 	testmetric{testlabel="1"} 1 1