diff --git a/adam-cli/src/main/scala/org/bdgenomics/adam/cli/Reads2Coverage.scala b/adam-cli/src/main/scala/org/bdgenomics/adam/cli/Reads2Coverage.scala
index d1d1f2ca2c..7ff5771286 100644
--- a/adam-cli/src/main/scala/org/bdgenomics/adam/cli/Reads2Coverage.scala
+++ b/adam-cli/src/main/scala/org/bdgenomics/adam/cli/Reads2Coverage.scala
@@ -64,7 +64,7 @@ class Reads2Coverage(protected val args: Reads2CoverageArgs) extends BDGSparkCom
 
   def run(sc: SparkContext): Unit = {
 
-    val proj = Projection(contigName, start, end, cigar)
+    val proj = Projection(readMapped, contigName, start, end, cigar)
 
     // If saving strand specific coverage, require that only one direction is specified
     require(!(args.onlyNegativeStrands && args.onlyPositiveStrands),
diff --git a/adam-core/src/main/scala/org/bdgenomics/adam/rdd/read/AlignmentRecordRDD.scala b/adam-core/src/main/scala/org/bdgenomics/adam/rdd/read/AlignmentRecordRDD.scala
index 1fc514c4dd..cb819b7954 100644
--- a/adam-core/src/main/scala/org/bdgenomics/adam/rdd/read/AlignmentRecordRDD.scala
+++ b/adam-core/src/main/scala/org/bdgenomics/adam/rdd/read/AlignmentRecordRDD.scala
@@ -98,7 +98,17 @@ sealed trait AlignmentRecordRDD extends AvroReadGroupGenomicRDD[AlignmentRecord,
   def toCoverage(collapse: Boolean = true): CoverageRDD = {
     val covCounts =
       rdd.rdd
-        .flatMap(r => {
+        .filter(r => {
+          val readMapped = r.getReadMapped
+
+          // validate alignment fields
+          if (readMapped) {
+            require(r.getStart != null && r.getEnd != null && r.getContigName != null,
+              "Read was mapped but was missing alignment start/end/contig (%s).".format(r))
+          }
+
+          readMapped
+        }).flatMap(r => {
           val t: List[Long] = List.range(r.getStart, r.getEnd)
           t.map(n => (ReferenceRegion(r.getContigName, n, n + 1), 1))
         }).reduceByKey(_ + _)
diff --git a/adam-core/src/test/scala/org/bdgenomics/adam/rdd/read/AlignmentRecordRDDSuite.scala b/adam-core/src/test/scala/org/bdgenomics/adam/rdd/read/AlignmentRecordRDDSuite.scala
index c15ac5d559..1e94be6fb5 100644
--- a/adam-core/src/test/scala/org/bdgenomics/adam/rdd/read/AlignmentRecordRDDSuite.scala
+++ b/adam-core/src/test/scala/org/bdgenomics/adam/rdd/read/AlignmentRecordRDDSuite.scala
@@ -85,6 +85,17 @@ class AlignmentRecordRDDSuite extends ADAMFunSuite {
     assert(expectedSortedReads === mapped)
   }
 
+  sparkTest("coverage does not fail on unmapped reads") {
+    val inputPath = testFile("unmapped.sam")
+    val reads: AlignmentRecordRDD = sc.loadAlignments(inputPath)
+      .transform(rdd => {
+        rdd.filter(!_.getReadMapped)
+      })
+
+    val coverage = reads.toCoverage()
+    assert(coverage.rdd.count === 0)
+  }
+
   sparkTest("computes coverage") {
     val inputPath = testFile("artificial.sam")
     val reads: AlignmentRecordRDD = sc.loadAlignments(inputPath)