diff --git a/Cargo.lock b/Cargo.lock
index 7a54006..c0f9756 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -6,6 +6,7 @@ dependencies = [
  "atty 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "clap 2.26.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "ignore 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num_cpus 1.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "regex 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -122,6 +123,14 @@ dependencies = [
  "libc 0.2.30 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "num_cpus"
+version = "1.6.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "libc 0.2.30 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "regex"
 version = "0.2.2"
@@ -249,6 +258,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum libc 0.2.30 (registry+https://github.com/rust-lang/crates.io-index)" = "2370ca07ec338939e356443dac2296f581453c35fe1e3a3ed06023c49435f915"
 "checksum log 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)" = "880f77541efa6e5cc74e76910c9884d9859683118839d6a1dc3b11e63512565b"
 "checksum memchr 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)" = "1dbccc0e46f1ea47b9f17e6d67c5a96bd27030519c519c9c91327e31275a47b4"
+"checksum num_cpus 1.6.2 (registry+https://github.com/rust-lang/crates.io-index)" = "aec53c34f2d0247c5ca5d32cca1478762f301740468ee9ee6dcb7a0dd7a0c584"
 "checksum regex 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "1731164734096285ec2a5ec7fea5248ae2f5485b3feeb0115af4fda2183b2d1b"
 "checksum regex-syntax 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)" = "ad890a5eef7953f55427c50575c680c42841653abd2b028b68cd223d157f62db"
 "checksum same-file 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)" = "d931a44fdaa43b8637009e7632a02adc4f2b2e0733c08caa4cf00e8da4a117a7"
diff --git a/Cargo.toml b/Cargo.toml
index 5c68238..f747681 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -9,3 +9,4 @@ clap = "2.26.0"
 atty = "0.2"
 regex = "0.2"
 ignore = "0.2"
+num_cpus = "1.6.2"
diff --git a/src/main.rs b/src/main.rs
index d917ec9..268b499 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -4,6 +4,7 @@ extern crate ansi_term;
 extern crate atty;
 extern crate regex;
 extern crate ignore;
+extern crate num_cpus;
 
 pub mod lscolors;
 pub mod fshelper;
@@ -67,7 +68,7 @@ struct FdOptions {
     max_depth: Option<usize>,
 
     /// The number of threads to use.
-    threads: Option<usize>,
+    threads: usize,
 
     /// Time to buffer results internally before streaming to the console. This is useful to
     /// provide a sorted output, in case the total execution time is shorter than
@@ -209,7 +210,7 @@ fn scan(root: &Path, pattern: Arc<Regex>, base: &Path, config: Arc<FdOptions>) {
                      .git_exclude(config.read_ignore)
                      .follow_links(config.follow_links)
                      .max_depth(config.max_depth)
-                     .threads(config.threads.unwrap_or(0))
+                     .threads(config.threads)
                      .build_parallel();
 
     // Spawn the thread that receives all results through the channel.
@@ -433,8 +434,12 @@ fn main() {
         null_separator:    matches.is_present("null_separator"),
         max_depth:         matches.value_of("depth")
                                    .and_then(|n| usize::from_str_radix(n, 10).ok()),
-        threads:           matches.value_of("threads")
-                                   .and_then(|n| usize::from_str_radix(n, 10).ok()),
+        threads:           std::cmp::max(
+                             matches.value_of("threads")
+                                    .and_then(|n| usize::from_str_radix(n, 10).ok())
+                                    .unwrap_or(num_cpus::get()),
+                             1
+                           ),
         max_buffer_time:   matches.value_of("max-buffer-time")
                                   .and_then(|n| u64::from_str_radix(n, 10).ok())
                                   .map(time::Duration::from_millis),