--- a/flye/assembly/scaffolder.py
+++ b/flye/assembly/scaffolder.py
@@ -12,7 +12,6 @@
 
 import flye.utils.fasta_parser as fp
 import flye.config.py_cfg as cfg
-from six import iteritems
 
 logger = logging.getLogger()
 
@@ -128,7 +127,7 @@
             contigs_stats[tokens[0]].coverage = tokens[2]
 
     scaffolds_stats = {}
-    for scf, scf_seq in iteritems(scaffolds):
+    for scf, scf_seq in scaffolds.items():
         scaffolds_stats[scf] = SeqStats(scf)
         scf_length = sum([int(contigs_stats[unsigned(c)].length) for c in scf_seq])
         scf_length += (len(scf_seq) - 1) * cfg.vals["scaffold_gap"]
--- a/flye/config/configurator.py
+++ b/flye/config/configurator.py
@@ -12,7 +12,6 @@
 
 import flye.utils.fasta_parser as fp
 import flye.config.py_cfg as cfg
-from six import iteritems
 
 
 logger = logging.getLogger()
@@ -37,7 +36,7 @@
     passing_reads = 0
 
     for read_file in args.reads:
-        for _, seq_len in iteritems(fp.read_sequence_lengths(read_file)):
+        for _, seq_len in fp.read_sequence_lengths(read_file).items():
             if seq_len > MAX_READ_LEN:
                 raise ConfigException("Length of single read in '{}' exceeded maximum ({})".format(read_file, MAX_READ_LEN))
             if seq_len > lowest_read_len:
--- a/flye/polishing/alignment.py
+++ b/flye/polishing/alignment.py
@@ -18,7 +18,6 @@
 import flye.utils.fasta_parser as fp
 from flye.utils.utils import which, get_median
 from flye.utils.sam_parser import AlignmentException
-from six import iteritems
 
 
 
@@ -47,7 +46,7 @@
 def get_contigs_info(contigs_file):
     contigs_info = {}
     contigs_fasta = fp.read_sequence_dict(contigs_file)
-    for ctg_id, ctg_seq in iteritems(contigs_fasta):
+    for ctg_id, ctg_seq in contigs_fasta.items():
         contig_type = ctg_id.split("_")[0]
         contigs_info[ctg_id] = ContigInfo(ctg_id, len(ctg_seq),
                                           contig_type)
--- a/flye/polishing/consensus.py
+++ b/flye/polishing/consensus.py
@@ -11,7 +11,6 @@
 import logging
 from collections import defaultdict
 
-from six import itervalues
 
 import multiprocessing
 import traceback
@@ -160,10 +159,10 @@
         pos_nucl = elem.nucl
 
         ins_group.clear()
-        for ins_str in itervalues(pos_insertions):
+        for ins_str in pos_insertions.values():
             ins_group[ins_str] += 1
 
-        match_and_del_num = sum(itervalues(pos_matches))
+        match_and_del_num = sum(pos_matches.values())
         del_num = pos_matches["-"]
         num_ins = len(pos_insertions)
 
--- a/flye/polishing/polish.py
+++ b/flye/polishing/polish.py
@@ -21,7 +21,6 @@
 import flye.utils.fasta_parser as fp
 from flye.utils.utils import which
 import flye.config.py_cfg as cfg
-from six import iteritems
 
 
 
@@ -329,7 +328,7 @@
     polished_fasta = {}
     polished_stats = {}
     polished_coverages = {}
-    for ctg_id, seqs in iteritems(consensuses):
+    for ctg_id, seqs in consensuses.items():
         seqs.sort(key=lambda p: (p[0], p[1]))
         sorted_seqs = [p[3] for p in seqs]
         bubble_coverages = [(len(p[3]), p[2]) for p in seqs]
--- a/flye/short_plasmids/circular_sequences.py
+++ b/flye/short_plasmids/circular_sequences.py
@@ -9,7 +9,6 @@
 import flye.utils.fasta_parser as fp
 from flye.utils.sam_parser import read_paf, read_paf_grouped
 import logging
-from six import iteritems
 
 
 logger = logging.getLogger()
@@ -47,7 +46,7 @@
 def trim_circular_reads(circular_reads, unmapped_reads):
     trimmed_circular_reads = dict()
 
-    for i, (read, hit) in enumerate(iteritems(circular_reads)):
+    for i, (read, hit) in enumerate(circular_reads.items()):
         sequence = unmapped_reads[read][:hit.target_start].upper()
         trimmed_circular_reads["circular_read_" + str(i)] = sequence
 
--- a/flye/short_plasmids/unmapped_reads.py
+++ b/flye/short_plasmids/unmapped_reads.py
@@ -9,7 +9,6 @@
 from flye.utils.sam_parser import read_paf_grouped
 import logging
 from collections import defaultdict
-from six import iteritems
 
 
 logger = logging.getLogger()
@@ -76,7 +75,7 @@
                 contigs = mapping_rates.get(hdr)
                 if contigs is not None:
                     is_unmapped = True
-                    for _, mapping_rate in iteritems(contigs):
+                    for _, mapping_rate in contigs.items():
                         if mapping_rate >= mapping_rate_threshold:
                             is_unmapped = False
 
--- a/flye/trestle/graph_resolver.py
+++ b/flye/trestle/graph_resolver.py
@@ -13,7 +13,6 @@
 
 import flye.utils.fasta_parser as fp
 from flye.repeat_graph.graph_alignment import iter_alignments
-from six import iteritems
 
 
 logger = logging.getLogger()
@@ -146,7 +145,7 @@
 
 def dump_repeats(repeats_info, filename):
     with open(filename, "w") as f:
-        for repeat_id, info in iteritems(repeats_info):
+        for repeat_id, info in repeats_info.items():
             f.write("#Repeat {0}\t{1}\n\n".format(repeat_id, info.multiplicity))
 
             f.write("#All reads\t{0}\n".format(len(info.all_reads)))
--- a/flye/utils/sam_parser.py
+++ b/flye/utils/sam_parser.py
@@ -33,7 +33,6 @@
     _BYTES = str.encode
 
 
-from six import iteritems
 
 import flye.utils.fasta_parser as fp
 from flye.utils.utils import get_median
@@ -209,7 +208,7 @@
 
         #self.shared_manager = multiprocessing.Manager()
         self.ref_fasta = dict() if multiproc_manager == None else multiproc_manager.dict()
-        for (h, s) in iteritems(reference_fasta):
+        for (h, s) in reference_fasta.items():
             self.ref_fasta[_BYTES(h)] = _BYTES(s)
 
     def get_region_sequence(self, region_id, region_start=None, region_end=None):