diff --git a/kipoiseq/utils.py b/kipoiseq/utils.py
index 5610c37..5d97703 100644
--- a/kipoiseq/utils.py
+++ b/kipoiseq/utils.py
@@ -1,5 +1,7 @@
-import numpy as np
 from six import string_types
+import numpy as np
+import pyranges
+from kipoiseq.extractors import MultiSampleVCF, FastaStringExtractor
 
 
 # alphabets:
@@ -34,6 +36,62 @@ def parse_dtype(dtype):
         try:
             return eval(dtype)
         except Exception as e:
-            raise ValueError("Unable to parse dtype: {}. \nException: {}".format(dtype, e))
+            raise ValueError(
+                "Unable to parse dtype: {}. \nException: {}".format(dtype, e))
     else:
         return dtype
+
+
+def _get_chrom_annotation(source):
+    if type(source) == FastaStringExtractor:
+        return set(source.fasta.keys())
+    elif type(source) == MultiSampleVCF:
+        return set(source.seqnames)
+    elif type(source) == pyranges.PyRanges:
+        return set(source.Chromosome)
+    else:
+        raise ValueError('source `%s` is not valid is not valid because '
+                         ' source type `%s` is not supported.'
+                         % (repr(source), type(source)))
+
+
+def compare_chrom_annotation(sources, strategy='some', core_chroms=None):
+    """Compares chromosome annotations from different sources.
+        Throws exception iif annotations are not compatible.
+
+    # Arguments:
+        sources: list of different objects. vcf, fasta, pyranges are valid.
+        strategy: comparison strategy. `some` means some intersection excepted
+          or  `all` all chromosomes should be same.
+        core_chroms: chromosomes must exist.
+
+    # Returns:
+        chroms common cross files.
+
+    # Example:
+        ```python
+          >>> sources = [
+                MultiSampleVCF(...),
+                FastaStringExtractor(...),
+                pyranges,
+                pyranges,
+                MultiSampleVCF(...)
+              ]
+          >>> compare_chrom_annotation(sources, strategy='all')
+        ```
+    """
+    if not len(sources) > 1:
+        raise ValueError(
+            'At least two item should gived as sources to compare')
+
+    chroms = list(map(_get_chrom_annotation, sources))
+
+    if strategy == 'all':
+        assert all(chroms[0] == i for i in chroms), \
+            'chroms annotations are not all same.'
+        return chroms[0]
+    elif strategy == 'some':
+        chrom_intersect = set.intersection(*chroms)
+        assert len(chrom_intersect) > 0, \
+            'there is not intersection between chromosomes.'
+        return chrom_intersect
diff --git a/setup.py b/setup.py
index 4779d5e..59ff134 100755
--- a/setup.py
+++ b/setup.py
@@ -26,6 +26,7 @@
     "jedi",
     "pytest>=3.3.1",
     "pytest-xdist",  # running tests in parallel
+    "pytest-mock",
     "pytest-pep8",  # see https://github.com/kipoi/kipoi/issues/91
     "pytest-cov",
     "coveralls",
@@ -36,7 +37,7 @@
     # "genomelake",
     "keras",
     "tensorflow",
-    "pybedtools"
+    "pybedtools",
 ]
 
 setup(
diff --git a/tests/data/test.vcf.gz b/tests/data/test.vcf.gz
index d96030e..e37d849 100644
Binary files a/tests/data/test.vcf.gz and b/tests/data/test.vcf.gz differ
diff --git a/tests/data/test.vcf.gz.tbi b/tests/data/test.vcf.gz.tbi
index 303734c..b385012 100644
Binary files a/tests/data/test.vcf.gz.tbi and b/tests/data/test.vcf.gz.tbi differ
diff --git a/tests/test_3_utils.py b/tests/test_3_utils.py
index 7520b77..201bd3e 100644
--- a/tests/test_3_utils.py
+++ b/tests/test_3_utils.py
@@ -1,6 +1,10 @@
+from conftest import vcf_file, sample_5kb_fasta_file, example_intervals_bed
 import pytest
 import numpy as np
-from kipoiseq.utils import parse_alphabet, parse_dtype
+import pyranges
+from kipoiseq.extractors import FastaStringExtractor, MultiSampleVCF
+from kipoiseq.utils import parse_alphabet, parse_dtype, \
+    compare_chrom_annotation
 
 
 def test_parse_alphabet():
@@ -17,3 +21,33 @@ def test_parse_type():
     assert parse_dtype('float') == float
     assert parse_dtype(float) == float
     assert parse_dtype("np.float32") == np.float32
+
+
+def test_compare_chrom_annotation():
+    sources = [
+        MultiSampleVCF(vcf_file),
+        FastaStringExtractor(sample_5kb_fasta_file),
+        pyranges.read_bed(example_intervals_bed)
+    ]
+
+    with pytest.raises(ValueError):
+        assert compare_chrom_annotation([])
+
+    with pytest.raises(ValueError):
+        assert compare_chrom_annotation([object()])
+
+    assert compare_chrom_annotation(sources) == {'chr1'}
+    assert compare_chrom_annotation(sources, strategy='all') == {'chr1'}
+
+    with pytest.raises(AssertionError) as exception:
+        sources[1].fasta = {'chr1': '', 'chr2': '', 'chr3': ''}
+        compare_chrom_annotation(sources, strategy='all')
+
+    assert str(exception.value) == 'chroms annotations are not all same.'
+
+    assert compare_chrom_annotation(sources) == {'chr1'}
+
+    with pytest.raises(AssertionError) as exception:
+        sources[1].fasta = {'chr2': '', 'chr3': ''}
+        compare_chrom_annotation(sources)
+    assert str(exception.value) == 'there is not intersection between chromosomes.'