diff --git a/moshi/src/main/java/com/squareup/moshi/BufferedSourceJsonReader.java b/moshi/src/main/java/com/squareup/moshi/BufferedSourceJsonReader.java
index f31bdda..6362d01 100644
--- a/moshi/src/main/java/com/squareup/moshi/BufferedSourceJsonReader.java
+++ b/moshi/src/main/java/com/squareup/moshi/BufferedSourceJsonReader.java
@@ -17,6 +17,7 @@ package com.squareup.moshi;
 
 import java.io.EOFException;
 import java.io.IOException;
+import java.math.BigDecimal;
 import okio.Buffer;
 import okio.BufferedSource;
 import okio.ByteString;
@@ -718,15 +719,11 @@ final class BufferedSourceJsonReader extends JsonReader {
     }
 
     peeked = PEEKED_BUFFERED;
-    double asDouble;
+    long result;
     try {
-      asDouble = Double.parseDouble(peekedString);
-    } catch (NumberFormatException e) {
-      throw new JsonDataException("Expected a long but was " + peekedString
-          + " at path " + getPath());
-    }
-    long result = (long) asDouble;
-    if (result != asDouble) { // Make sure no precision was lost casting to 'long'.
+      BigDecimal asDecimal = new BigDecimal(peekedString);
+      result = asDecimal.longValueExact();
+    } catch (NumberFormatException | ArithmeticException e) {
       throw new JsonDataException("Expected a long but was " + peekedString
           + " at path " + getPath());
     }
diff --git a/moshi/src/test/java/com/squareup/moshi/BufferedSourceJsonReaderTest.java b/moshi/src/test/java/com/squareup/moshi/BufferedSourceJsonReaderTest.java
index 8927e42..7a0c2b1 100644
--- a/moshi/src/test/java/com/squareup/moshi/BufferedSourceJsonReaderTest.java
+++ b/moshi/src/test/java/com/squareup/moshi/BufferedSourceJsonReaderTest.java
@@ -617,11 +617,7 @@ public final class BufferedSourceJsonReaderTest {
     }
   }
 
-  /**
-   * This test fails because there's no double for 9223372036854775808, and our
-   * long parsing uses Double.parseDouble() for fractional values.
-   */
-  @Test @Ignore public void peekLargerThanLongMaxValue() throws IOException {
+  @Test public void peekLargerThanLongMaxValue() throws IOException {
     JsonReader reader = newReader("[9223372036854775808]");
     reader.setLenient(true);
     reader.beginArray();
@@ -633,11 +629,19 @@ public final class BufferedSourceJsonReaderTest {
     }
   }
 
-  /**
-   * This test fails because there's no double for -9223372036854775809, and our
-   * long parsing uses Double.parseDouble() for fractional values.
-   */
-  @Test @Ignore public void peekLargerThanLongMinValue() throws IOException {
+  @Test public void precisionNotDiscarded() throws IOException {
+    JsonReader reader = newReader("[9223372036854775806.5]");
+    reader.setLenient(true);
+    reader.beginArray();
+    assertThat(reader.peek()).isEqualTo(NUMBER);
+    try {
+      reader.nextLong();
+      fail();
+    } catch (JsonDataException expected) {
+    }
+  }
+
+  @Test public void peekLargerThanLongMinValue() throws IOException {
     JsonReader reader = newReader("[-9223372036854775809]");
     reader.setLenient(true);
     reader.beginArray();
@@ -650,11 +654,7 @@ public final class BufferedSourceJsonReaderTest {
     assertThat(reader.nextDouble()).isEqualTo(-9223372036854775809d);
   }
 
-  /**
-   * This test fails because there's no double for 9223372036854775806, and
-   * our long parsing uses Double.parseDouble() for fractional values.
-   */
-  @Test @Ignore public void highPrecisionLong() throws IOException {
+  @Test public void highPrecisionLong() throws IOException {
     String json = "[9223372036854775806.000]";
     JsonReader reader = newReader(json);
     reader.beginArray();
diff --git a/moshi/src/test/java/com/squareup/moshi/MoshiTest.java b/moshi/src/test/java/com/squareup/moshi/MoshiTest.java
index 7033d1a..ab8b6f5 100644
--- a/moshi/src/test/java/com/squareup/moshi/MoshiTest.java
+++ b/moshi/src/test/java/com/squareup/moshi/MoshiTest.java
@@ -433,21 +433,19 @@ public final class MoshiTest {
     assertThat(adapter.fromJson("9223372036854775807")).isEqualTo(Long.MAX_VALUE);
     assertThat(adapter.toJson(Long.MAX_VALUE)).isEqualTo("9223372036854775807");
 
-    // TODO: This is a bug?
-    assertThat(adapter.fromJson("9223372036854775808")).isEqualTo(Long.MAX_VALUE); // wtf?
-    //try {
-    //  adapter.fromJson("9223372036854775808");
-    //  fail();
-    //} catch (NumberFormatException expected) {
-    //  assertThat(expected).hasMessage("Expected a long but was 9223372036854775808 at path $");
-    //}
-    //
-    //try {
-    //  adapter.fromJson("-9223372036854775809");
-    //  fail();
-    //} catch (NumberFormatException expected) {
-    //  assertThat(expected).hasMessage("Expected a long but was -9223372036854775809 at path $");
-    //}
+    try {
+      adapter.fromJson("9223372036854775808");
+      fail();
+    } catch (JsonDataException expected) {
+      assertThat(expected).hasMessage("Expected a long but was 9223372036854775808 at path $");
+    }
+
+    try {
+      adapter.fromJson("-9223372036854775809");
+      fail();
+    } catch (JsonDataException expected) {
+      assertThat(expected).hasMessage("Expected a long but was -9223372036854775809 at path $");
+    }
 
     // Nulls not allowed for long.class
     try {