diff --git a/src/NzbDrone.Core.Test/SeriesStatsTests/SeriesStatisticsFixture.cs b/src/NzbDrone.Core.Test/SeriesStatsTests/SeriesStatisticsFixture.cs
index 980107237..254b4e987 100644
--- a/src/NzbDrone.Core.Test/SeriesStatsTests/SeriesStatisticsFixture.cs
+++ b/src/NzbDrone.Core.Test/SeriesStatsTests/SeriesStatisticsFixture.cs
@@ -4,6 +4,7 @@ using System.Linq;
 using FizzWare.NBuilder;
 using FluentAssertions;
 using NUnit.Framework;
+using NzbDrone.Common.Extensions;
 using NzbDrone.Core.Languages;
 using NzbDrone.Core.MediaFiles;
 using NzbDrone.Core.Qualities;
@@ -180,5 +181,25 @@ namespace NzbDrone.Core.Test.SeriesStatsTests
             stats.Should().HaveCount(1);
             stats.First().SizeOnDisk.Should().Be(_episodeFile.Size);
         }
+
+        [Test]
+        public void should_not_duplicate_size_for_multi_episode_files()
+        {
+            GivenEpisodeWithFile();
+            GivenEpisode();
+            GivenEpisodeFile();
+
+            var episode2 = _episode.JsonClone();
+
+            episode2.Id = 0;
+            episode2.EpisodeNumber += 1;
+
+            Db.Insert(episode2);
+
+            var stats = Subject.SeriesStatistics();
+
+            stats.Should().HaveCount(1);
+            stats.First().SizeOnDisk.Should().Be(_episodeFile.Size);
+        }
     }
 }
diff --git a/src/NzbDrone.Core/SeriesStats/SeriesStatisticsRepository.cs b/src/NzbDrone.Core/SeriesStats/SeriesStatisticsRepository.cs
index f267f369f..fd854d75a 100644
--- a/src/NzbDrone.Core/SeriesStats/SeriesStatisticsRepository.cs
+++ b/src/NzbDrone.Core/SeriesStats/SeriesStatisticsRepository.cs
@@ -1,7 +1,6 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
-using System.Text;
 using Dapper;
 using NzbDrone.Core.Datastore;
 using NzbDrone.Core.MediaFiles;
@@ -17,7 +16,8 @@ namespace NzbDrone.Core.SeriesStats
 
     public class SeriesStatisticsRepository : ISeriesStatisticsRepository
     {
-        private const string _selectTemplate = "SELECT /**select**/ FROM Episodes /**join**/ /**innerjoin**/ /**leftjoin**/ /**where**/ /**groupby**/ /**having**/ /**orderby**/";
+        private const string _selectEpisodesTemplate = "SELECT /**select**/ FROM Episodes /**join**/ /**innerjoin**/ /**leftjoin**/ /**where**/ /**groupby**/ /**having**/ /**orderby**/";
+        private const string _selectEpisodeFilesTemplate = "SELECT /**select**/ FROM EpisodeFiles /**join**/ /**innerjoin**/ /**leftjoin**/ /**where**/ /**groupby**/ /**having**/ /**orderby**/";
 
         private readonly IMainDatabase _database;
 
@@ -29,18 +29,34 @@ namespace NzbDrone.Core.SeriesStats
         public List<SeasonStatistics> SeriesStatistics()
         {
             var time = DateTime.UtcNow;
-            return Query(Builder(time));
+            return MapResults(Query(EpisodesBuilder(time), _selectEpisodesTemplate),
+                Query(EpisodeFilesBuilder(), _selectEpisodeFilesTemplate));
         }
 
         public List<SeasonStatistics> SeriesStatistics(int seriesId)
         {
             var time = DateTime.UtcNow;
-            return Query(Builder(time).Where<Episode>(x => x.SeriesId == seriesId));
+
+            return MapResults(Query(EpisodesBuilder(time).Where<Episode>(x => x.SeriesId == seriesId), _selectEpisodesTemplate),
+                Query(EpisodeFilesBuilder().Where<EpisodeFile>(x => x.SeriesId == seriesId), _selectEpisodeFilesTemplate));
         }
 
-        private List<SeasonStatistics> Query(SqlBuilder builder)
+        private List<SeasonStatistics> MapResults(List<SeasonStatistics> episodesResult, List<SeasonStatistics> filesResult)
         {
-            var sql = builder.AddTemplate(_selectTemplate).LogQuery();
+            episodesResult.ForEach(e =>
+            {
+                var file = filesResult.SingleOrDefault(f => f.SeriesId == e.SeriesId & f.SeasonNumber == e.SeasonNumber);
+
+                e.SizeOnDisk = file?.SizeOnDisk ?? 0;
+                e.ReleaseGroupsString = file?.ReleaseGroupsString;
+            });
+
+            return episodesResult;
+        }
+
+        private List<SeasonStatistics> Query(SqlBuilder builder, string template)
+        {
+            var sql = builder.AddTemplate(template).LogQuery();
 
             using (var conn = _database.OpenConnection())
             {
@@ -48,24 +64,33 @@ namespace NzbDrone.Core.SeriesStats
             }
         }
 
-        private SqlBuilder Builder(DateTime currentDate)
+        private SqlBuilder EpisodesBuilder(DateTime currentDate)
         {
             var parameters = new DynamicParameters();
             parameters.Add("currentDate", currentDate, null);
+
             return new SqlBuilder()
             .Select(@"Episodes.SeriesId AS SeriesId,
                              Episodes.SeasonNumber,
-                             SUM(COALESCE(EpisodeFiles.Size, 0)) AS SizeOnDisk,
-                             GROUP_CONCAT(EpisodeFiles.ReleaseGroup, '|') AS ReleaseGroupsString,
                              COUNT(*) AS TotalEpisodeCount,
                              SUM(CASE WHEN AirdateUtc <= @currentDate OR EpisodeFileId > 0 THEN 1 ELSE 0 END) AS AvailableEpisodeCount,
                              SUM(CASE WHEN (Monitored = 1 AND AirdateUtc <= @currentDate) OR EpisodeFileId > 0 THEN 1 ELSE 0 END) AS EpisodeCount,
                              SUM(CASE WHEN EpisodeFileId > 0 THEN 1 ELSE 0 END) AS EpisodeFileCount,
                              MIN(CASE WHEN AirDateUtc < @currentDate OR EpisodeFileId > 0 OR Monitored = 0 THEN NULL ELSE AirDateUtc END) AS NextAiringString,
                              MAX(CASE WHEN AirDateUtc >= @currentDate OR EpisodeFileId = 0 AND Monitored = 0 THEN NULL ELSE AirDateUtc END) AS PreviousAiringString", parameters)
-            .LeftJoin<Episode, EpisodeFile>((t, f) => t.EpisodeFileId == f.Id)
             .GroupBy<Episode>(x => x.SeriesId)
             .GroupBy<Episode>(x => x.SeasonNumber);
         }
+
+        private SqlBuilder EpisodeFilesBuilder()
+        {
+            return new SqlBuilder()
+                .Select(@"SeriesId,
+                            SeasonNumber,
+                            SUM(COALESCE(Size, 0)) AS SizeOnDisk,
+                            GROUP_CONCAT(ReleaseGroup, '|') AS ReleaseGroupsString")
+                .GroupBy<EpisodeFile>(x => x.SeriesId)
+                .GroupBy<EpisodeFile>(x => x.SeasonNumber);
+        }
     }
 }